wolfSSL SSL/TLS library, support up to TLS1.3

Dependents:   CyaSSL-Twitter-OAuth4Tw Example-client-tls-cert TwitterReader TweetTest ... more

Revision:
13:f67a6c6013ca
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wolfcrypt/src/pkcs7.c	Tue Aug 22 10:48:22 2017 +0000
@@ -0,0 +1,4631 @@
+/* pkcs7.c
+ *
+ * Copyright (C) 2006-2016 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL.
+ *
+ * wolfSSL is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfSSL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+
+#ifdef HAVE_CONFIG_H
+    #include <config.h>
+#endif
+
+#include <wolfssl/wolfcrypt/settings.h>
+
+#ifdef HAVE_PKCS7
+
+#include <wolfssl/wolfcrypt/pkcs7.h>
+#include <wolfssl/wolfcrypt/error-crypt.h>
+#include <wolfssl/wolfcrypt/logging.h>
+#include <wolfssl/wolfcrypt/hash.h>
+#ifndef NO_RSA
+    #include <wolfssl/wolfcrypt/rsa.h>
+#endif
+#ifdef HAVE_ECC
+    #include <wolfssl/wolfcrypt/ecc.h>
+#endif
+#ifdef NO_INLINE
+    #include <wolfssl/wolfcrypt/misc.h>
+#else
+    #define WOLFSSL_MISC_INCLUDED
+    #include <wolfcrypt/src/misc.c>
+#endif
+
+
+/* direction for processing, encoding or decoding */
+typedef enum {
+    WC_PKCS7_ENCODE,
+    WC_PKCS7_DECODE
+} pkcs7Direction;
+
+#define MAX_PKCS7_DIGEST_SZ (MAX_SEQ_SZ + MAX_ALGO_SZ + \
+                             MAX_OCTET_STR_SZ + WC_MAX_DIGEST_SIZE)
+
+
+/* placed ASN.1 contentType OID into *output, return idx on success,
+ * 0 upon failure */
+static int wc_SetContentType(int pkcs7TypeOID, byte* output)
+{
+    /* PKCS#7 content types, RFC 2315, section 14 */
+    const byte pkcs7[]              = { 0x2A, 0x86, 0x48, 0x86, 0xF7,
+                                               0x0D, 0x01, 0x07 };
+    const byte data[]               = { 0x2A, 0x86, 0x48, 0x86, 0xF7,
+                                               0x0D, 0x01, 0x07, 0x01 };
+    const byte signedData[]         = { 0x2A, 0x86, 0x48, 0x86, 0xF7,
+                                               0x0D, 0x01, 0x07, 0x02};
+    const byte envelopedData[]      = { 0x2A, 0x86, 0x48, 0x86, 0xF7,
+                                               0x0D, 0x01, 0x07, 0x03 };
+    const byte signedAndEnveloped[] = { 0x2A, 0x86, 0x48, 0x86, 0xF7,
+                                               0x0D, 0x01, 0x07, 0x04 };
+    const byte digestedData[]       = { 0x2A, 0x86, 0x48, 0x86, 0xF7,
+                                               0x0D, 0x01, 0x07, 0x05 };
+    const byte encryptedData[]      = { 0x2A, 0x86, 0x48, 0x86, 0xF7,
+                                               0x0D, 0x01, 0x07, 0x06 };
+
+    int idSz;
+    int typeSz = 0, idx = 0;
+    const byte* typeName = 0;
+    byte ID_Length[MAX_LENGTH_SZ];
+
+    switch (pkcs7TypeOID) {
+        case PKCS7_MSG:
+            typeSz = sizeof(pkcs7);
+            typeName = pkcs7;
+            break;
+
+        case DATA:
+            typeSz = sizeof(data);
+            typeName = data;
+            break;
+
+        case SIGNED_DATA:
+            typeSz = sizeof(signedData);
+            typeName = signedData;
+            break;
+
+        case ENVELOPED_DATA:
+            typeSz = sizeof(envelopedData);
+            typeName = envelopedData;
+            break;
+
+        case SIGNED_AND_ENVELOPED_DATA:
+            typeSz = sizeof(signedAndEnveloped);
+            typeName = signedAndEnveloped;
+            break;
+
+        case DIGESTED_DATA:
+            typeSz = sizeof(digestedData);
+            typeName = digestedData;
+            break;
+
+        case ENCRYPTED_DATA:
+            typeSz = sizeof(encryptedData);
+            typeName = encryptedData;
+            break;
+
+        default:
+            WOLFSSL_MSG("Unknown PKCS#7 Type");
+            return 0;
+    };
+
+    idSz  = SetLength(typeSz, ID_Length);
+    output[idx++] = ASN_OBJECT_ID;
+    XMEMCPY(output + idx, ID_Length, idSz);
+    idx += idSz;
+    XMEMCPY(output + idx, typeName, typeSz);
+    idx += typeSz;
+
+    return idx;
+}
+
+
+/* get ASN.1 contentType OID sum, return 0 on success, <0 on failure */
+static int wc_GetContentType(const byte* input, word32* inOutIdx, word32* oid,
+                             word32 maxIdx)
+{
+    WOLFSSL_ENTER("wc_GetContentType");
+    if (GetObjectId(input, inOutIdx, oid, oidIgnoreType, maxIdx) < 0)
+        return ASN_PARSE_E;
+
+    return 0;
+}
+
+
+/* return block size for algorithm represented by oid, or <0 on error */
+static int wc_PKCS7_GetOIDBlockSize(int oid)
+{
+    int blockSz;
+
+    switch (oid) {
+#ifndef NO_AES
+        case AES128CBCb:
+        case AES192CBCb:
+        case AES256CBCb:
+            blockSz = AES_BLOCK_SIZE;
+            break;
+#endif
+#ifndef NO_DES3
+        case DESb:
+        case DES3b:
+            blockSz = DES_BLOCK_SIZE;
+            break;
+#endif
+        default:
+            WOLFSSL_MSG("Unsupported content cipher type");
+            return ALGO_ID_E;
+    };
+
+    return blockSz;
+}
+
+
+/* get key size for algorithm represented by oid, or <0 on error */
+static int wc_PKCS7_GetOIDKeySize(int oid)
+{
+    int blockKeySz;
+
+    switch (oid) {
+#ifndef NO_AES
+        case AES128CBCb:
+        case AES128_WRAP:
+            blockKeySz = 16;
+            break;
+
+        case AES192CBCb:
+        case AES192_WRAP:
+            blockKeySz = 24;
+            break;
+
+        case AES256CBCb:
+        case AES256_WRAP:
+            blockKeySz = 32;
+            break;
+#endif
+#ifndef NO_DES3
+        case DESb:
+            blockKeySz = DES_KEYLEN;
+            break;
+
+        case DES3b:
+            blockKeySz = DES3_KEYLEN;
+            break;
+#endif
+        default:
+            WOLFSSL_MSG("Unsupported content cipher type");
+            return ALGO_ID_E;
+    };
+
+    return blockKeySz;
+}
+
+
+/* This is to initialize a PKCS7 structure. It sets all values to 0 and can be
+ * used to set the heap hint.
+ *
+ * pkcs7 PKCS7 structure to initialize
+ * heap  memory heap hint for PKCS7 structure to use
+ * devId currently not used but a place holder for async operations
+ *
+ * returns 0 on success or a negative value for failure
+ */
+int wc_PKCS7_Init(PKCS7* pkcs7, void* heap, int devId)
+{
+    WOLFSSL_ENTER("wc_PKCS7_Init");
+
+    if (pkcs7 == NULL) {
+        return BAD_FUNC_ARG;
+    }
+
+    XMEMSET(pkcs7, 0, sizeof(PKCS7));
+    pkcs7->heap = heap;
+
+    (void)devId; /* silence unused warning */
+    return 0;
+}
+
+
+/* init PKCS7 struct with recipient cert, decode into DecodedCert
+ * NOTE: keeps previously set pkcs7 memory heap hint */
+int wc_PKCS7_InitWithCert(PKCS7* pkcs7, byte* cert, word32 certSz)
+{
+    int ret = 0;
+    void* heap;
+
+
+#ifdef WOLFSSL_HEAP_TEST
+    heap = (void*)WOLFSSL_HEAP_TEST;
+#else
+    heap = pkcs7->heap;
+#endif
+
+    XMEMSET(pkcs7, 0, sizeof(PKCS7));
+    pkcs7->heap = heap;
+
+    if (cert != NULL && certSz > 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        DecodedCert* dCert;
+
+        dCert = (DecodedCert*)XMALLOC(sizeof(DecodedCert), NULL,
+                                                       DYNAMIC_TYPE_PKCS7);
+        if (dCert == NULL)
+            return MEMORY_E;
+#else
+        DecodedCert stack_dCert;
+        DecodedCert* dCert = &stack_dCert;
+#endif
+
+        pkcs7->singleCert = cert;
+        pkcs7->singleCertSz = certSz;
+        InitDecodedCert(dCert, cert, certSz, pkcs7->heap);
+
+        ret = ParseCert(dCert, CA_TYPE, NO_VERIFY, 0);
+        if (ret < 0) {
+            FreeDecodedCert(dCert);
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(dCert, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+            return ret;
+        }
+
+        XMEMCPY(pkcs7->publicKey, dCert->publicKey, dCert->pubKeySize);
+        pkcs7->publicKeySz = dCert->pubKeySize;
+        pkcs7->publicKeyOID = dCert->keyOID;
+        XMEMCPY(pkcs7->issuerHash, dCert->issuerHash, KEYID_SIZE);
+        pkcs7->issuer = dCert->issuerRaw;
+        pkcs7->issuerSz = dCert->issuerRawLen;
+        XMEMCPY(pkcs7->issuerSn, dCert->serial, dCert->serialSz);
+        pkcs7->issuerSnSz = dCert->serialSz;
+        FreeDecodedCert(dCert);
+
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(dCert, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+    }
+
+    return ret;
+}
+
+
+/* free linked list of PKCS7DecodedAttrib structs */
+static void wc_PKCS7_FreeDecodedAttrib(PKCS7DecodedAttrib* attrib, void* heap)
+{
+    PKCS7DecodedAttrib* current;
+
+    if (attrib == NULL) {
+        return;
+    }
+
+    current = attrib;
+    while (current != NULL) {
+        PKCS7DecodedAttrib* next = current->next;
+        if (current->oid != NULL)  {
+            XFREE(current->oid, heap, DYNAMIC_TYPE_PKCS7);
+        }
+        if (current->value != NULL) {
+            XFREE(current->value, heap, DYNAMIC_TYPE_PKCS7);
+        }
+        XFREE(current, heap, DYNAMIC_TYPE_PKCS7);
+        current = next;
+    }
+
+    (void)heap;
+}
+
+
+/* releases any memory allocated by a PKCS7 initializer */
+void wc_PKCS7_Free(PKCS7* pkcs7)
+{
+    if (pkcs7 == NULL)
+        return;
+
+    wc_PKCS7_FreeDecodedAttrib(pkcs7->decodedAttrib, pkcs7->heap);
+}
+
+
+/* build PKCS#7 data content type */
+int wc_PKCS7_EncodeData(PKCS7* pkcs7, byte* output, word32 outputSz)
+{
+    static const byte oid[] =
+        { ASN_OBJECT_ID, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01,
+                         0x07, 0x01 };
+    byte seq[MAX_SEQ_SZ];
+    byte octetStr[MAX_OCTET_STR_SZ];
+    word32 seqSz;
+    word32 octetStrSz;
+    word32 oidSz = (word32)sizeof(oid);
+    int idx = 0;
+
+    octetStrSz = SetOctetString(pkcs7->contentSz, octetStr);
+    seqSz = SetSequence(pkcs7->contentSz + octetStrSz + oidSz, seq);
+
+    if (outputSz < pkcs7->contentSz + octetStrSz + oidSz + seqSz)
+        return BUFFER_E;
+
+    XMEMCPY(output, seq, seqSz);
+    idx += seqSz;
+    XMEMCPY(output + idx, oid, oidSz);
+    idx += oidSz;
+    XMEMCPY(output + idx, octetStr, octetStrSz);
+    idx += octetStrSz;
+    XMEMCPY(output + idx, pkcs7->content, pkcs7->contentSz);
+    idx += pkcs7->contentSz;
+
+    return idx;
+}
+
+
+typedef struct EncodedAttrib {
+    byte valueSeq[MAX_SEQ_SZ];
+        const byte* oid;
+        byte valueSet[MAX_SET_SZ];
+        const byte* value;
+    word32 valueSeqSz, oidSz, idSz, valueSetSz, valueSz, totalSz;
+} EncodedAttrib;
+
+
+typedef struct ESD {
+    wc_HashAlg  hash;
+    enum wc_HashType hashType;
+    byte contentDigest[WC_MAX_DIGEST_SIZE + 2]; /* content only + ASN.1 heading */
+    byte contentAttribsDigest[WC_MAX_DIGEST_SIZE];
+    byte encContentDigest[512];
+
+    byte outerSeq[MAX_SEQ_SZ];
+        byte outerContent[MAX_EXP_SZ];
+            byte innerSeq[MAX_SEQ_SZ];
+                byte version[MAX_VERSION_SZ];
+                byte digAlgoIdSet[MAX_SET_SZ];
+                    byte singleDigAlgoId[MAX_ALGO_SZ];
+
+                byte contentInfoSeq[MAX_SEQ_SZ];
+                    byte innerContSeq[MAX_EXP_SZ];
+                        byte innerOctets[MAX_OCTET_STR_SZ];
+
+                byte certsSet[MAX_SET_SZ];
+
+                byte signerInfoSet[MAX_SET_SZ];
+                    byte signerInfoSeq[MAX_SEQ_SZ];
+                        byte signerVersion[MAX_VERSION_SZ];
+                        byte issuerSnSeq[MAX_SEQ_SZ];
+                            byte issuerName[MAX_SEQ_SZ];
+                            byte issuerSn[MAX_SN_SZ];
+                        byte signerDigAlgoId[MAX_ALGO_SZ];
+                        byte digEncAlgoId[MAX_ALGO_SZ];
+                        byte signedAttribSet[MAX_SET_SZ];
+                            EncodedAttrib signedAttribs[6];
+                        byte signerDigest[MAX_OCTET_STR_SZ];
+    word32 innerOctetsSz, innerContSeqSz, contentInfoSeqSz;
+    word32 outerSeqSz, outerContentSz, innerSeqSz, versionSz, digAlgoIdSetSz,
+           singleDigAlgoIdSz, certsSetSz;
+    word32 signerInfoSetSz, signerInfoSeqSz, signerVersionSz,
+           issuerSnSeqSz, issuerNameSz, issuerSnSz,
+           signerDigAlgoIdSz, digEncAlgoIdSz, signerDigestSz;
+    word32 encContentDigestSz, signedAttribsSz, signedAttribsCount,
+           signedAttribSetSz;
+} ESD;
+
+
+static int EncodeAttributes(EncodedAttrib* ea, int eaSz,
+                                            PKCS7Attrib* attribs, int attribsSz)
+{
+    int i;
+    int maxSz = min(eaSz, attribsSz);
+    int allAttribsSz = 0;
+
+    for (i = 0; i < maxSz; i++)
+    {
+        int attribSz = 0;
+
+        ea[i].value = attribs[i].value;
+        ea[i].valueSz = attribs[i].valueSz;
+        attribSz += ea[i].valueSz;
+        ea[i].valueSetSz = SetSet(attribSz, ea[i].valueSet);
+        attribSz += ea[i].valueSetSz;
+        ea[i].oid = attribs[i].oid;
+        ea[i].oidSz = attribs[i].oidSz;
+        attribSz += ea[i].oidSz;
+        ea[i].valueSeqSz = SetSequence(attribSz, ea[i].valueSeq);
+        attribSz += ea[i].valueSeqSz;
+        ea[i].totalSz = attribSz;
+
+        allAttribsSz += attribSz;
+    }
+    return allAttribsSz;
+}
+
+
+static int FlattenAttributes(byte* output, EncodedAttrib* ea, int eaSz)
+{
+    int i, idx;
+
+    idx = 0;
+    for (i = 0; i < eaSz; i++) {
+        XMEMCPY(output + idx, ea[i].valueSeq, ea[i].valueSeqSz);
+        idx += ea[i].valueSeqSz;
+        XMEMCPY(output + idx, ea[i].oid, ea[i].oidSz);
+        idx += ea[i].oidSz;
+        XMEMCPY(output + idx, ea[i].valueSet, ea[i].valueSetSz);
+        idx += ea[i].valueSetSz;
+        XMEMCPY(output + idx, ea[i].value, ea[i].valueSz);
+        idx += ea[i].valueSz;
+    }
+    return 0;
+}
+
+
+#ifndef NO_RSA
+
+/* returns size of signature put into out, negative on error */
+static int wc_PKCS7_RsaSign(PKCS7* pkcs7, byte* in, word32 inSz, ESD* esd)
+{
+    int ret;
+    word32 idx;
+#ifdef WOLFSSL_SMALL_STACK
+    RsaKey* privKey;
+#else
+    RsaKey  stack_privKey;
+    RsaKey* privKey = &stack_privKey;
+#endif
+
+    if (pkcs7 == NULL || pkcs7->privateKey == NULL || pkcs7->rng == NULL ||
+        in == NULL || esd == NULL)
+        return BAD_FUNC_ARG;
+
+#ifdef WOLFSSL_SMALL_STACK
+    privKey = (RsaKey*)XMALLOC(sizeof(RsaKey), NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (privKey == NULL)
+        return MEMORY_E;
+#endif
+
+    ret = wc_InitRsaKey(privKey, pkcs7->heap);
+
+    if (ret == 0) {
+        idx = 0;
+        ret = wc_RsaPrivateKeyDecode(pkcs7->privateKey, &idx, privKey,
+                                     pkcs7->privateKeySz);
+    }
+
+    if (ret == 0) {
+        ret = wc_RsaSSL_Sign(in, inSz, esd->encContentDigest,
+                             sizeof(esd->encContentDigest),
+                             privKey, pkcs7->rng);
+    }
+
+    wc_FreeRsaKey(privKey);
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(privKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return ret;
+}
+
+#endif /* NO_RSA */
+
+
+#ifdef HAVE_ECC
+
+/* returns size of signature put into out, negative on error */
+static int wc_PKCS7_EcdsaSign(PKCS7* pkcs7, byte* in, word32 inSz, ESD* esd)
+{
+    int ret;
+    word32 outSz, idx;
+#ifdef WOLFSSL_SMALL_STACK
+    ecc_key* privKey;
+#else
+    ecc_key  stack_privKey;
+    ecc_key* privKey = &stack_privKey;
+#endif
+
+    if (pkcs7 == NULL || pkcs7->privateKey == NULL || pkcs7->rng == NULL ||
+        in == NULL || esd == NULL)
+        return BAD_FUNC_ARG;
+
+#ifdef WOLFSSL_SMALL_STACK
+    privKey = (ecc_key*)XMALLOC(sizeof(ecc_key), NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (privKey == NULL)
+        return MEMORY_E;
+#endif
+
+    ret = wc_ecc_init_ex(privKey, pkcs7->heap, INVALID_DEVID);
+
+    if (ret == 0) {
+        idx = 0;
+        ret = wc_EccPrivateKeyDecode(pkcs7->privateKey, &idx, privKey,
+                                     pkcs7->privateKeySz);
+    }
+
+    if (ret == 0) {
+        outSz = sizeof(esd->encContentDigest);
+        ret = wc_ecc_sign_hash(in, inSz, esd->encContentDigest,
+                               &outSz, pkcs7->rng, privKey);
+        if (ret == 0)
+            ret = (int)outSz;
+    }
+
+    wc_ecc_free(privKey);
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(privKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return ret;
+}
+
+#endif /* HAVE_ECC */
+
+
+/* builds up SignedData signed attributes, including default ones.
+ *
+ * pkcs7 - pointer to initialized PKCS7 structure
+ * esd   - pointer to initialized ESD structure, used for output
+ *
+ * return 0 on success, negative on error */
+static int wc_PKCS7_BuildSignedAttributes(PKCS7* pkcs7, ESD* esd,
+                    byte* contentTypeOid, word32 contentTypeOidSz,
+                    byte* contentType, word32 contentTypeSz,
+                    byte* messageDigestOid, word32 messageDigestOidSz)
+{
+    int hashSz;
+
+    PKCS7Attrib cannedAttribs[2];
+    word32 cannedAttribsCount;
+
+    if (pkcs7 == NULL || esd == NULL || contentTypeOid == NULL ||
+        contentType == NULL || messageDigestOid == NULL)
+        return BAD_FUNC_ARG;
+
+    hashSz = wc_HashGetDigestSize(esd->hashType);
+    if (hashSz < 0)
+        return hashSz;
+
+    cannedAttribsCount = sizeof(cannedAttribs)/sizeof(PKCS7Attrib);
+
+    cannedAttribs[0].oid     = contentTypeOid;
+    cannedAttribs[0].oidSz   = contentTypeOidSz;
+    cannedAttribs[0].value   = contentType;
+    cannedAttribs[0].valueSz = contentTypeSz;
+    cannedAttribs[1].oid     = messageDigestOid;
+    cannedAttribs[1].oidSz   = messageDigestOidSz;
+    cannedAttribs[1].value   = esd->contentDigest;
+    cannedAttribs[1].valueSz = hashSz + 2;  /* ASN.1 heading */
+
+    esd->signedAttribsCount += cannedAttribsCount;
+    esd->signedAttribsSz += EncodeAttributes(&esd->signedAttribs[0], 2,
+                                         cannedAttribs, cannedAttribsCount);
+
+    esd->signedAttribsCount += pkcs7->signedAttribsSz;
+    esd->signedAttribsSz += EncodeAttributes(&esd->signedAttribs[2], 4,
+                              pkcs7->signedAttribs, pkcs7->signedAttribsSz);
+
+    return 0;
+}
+
+
+/* gets correct encryption algo ID for SignedData, either RSAk or
+ * CTC_<hash>wECDSA, from pkcs7->publicKeyOID.
+ *
+ * pkcs7          - pointer to PKCS7 structure
+ * digEncAlgoId   - [OUT] output int to store correct algo ID in
+ * digEncAlgoType - [OUT] output for algo ID type
+ *
+ * return 0 on success, negative on error */
+static int wc_PKCS7_SignedDataGetEncAlgoId(PKCS7* pkcs7, int* digEncAlgoId,
+                                           int* digEncAlgoType)
+{
+    int algoId   = 0;
+    int algoType = 0;
+
+    if (pkcs7 == NULL || digEncAlgoId == NULL || digEncAlgoType == NULL)
+        return BAD_FUNC_ARG;
+
+    if (pkcs7->publicKeyOID == RSAk) {
+
+        algoId = pkcs7->encryptOID;
+        algoType = oidKeyType;
+
+    } else if (pkcs7->publicKeyOID == ECDSAk) {
+
+        algoType = oidSigType;
+
+        switch (pkcs7->hashOID) {
+            case SHAh:
+                algoId = CTC_SHAwECDSA;
+                break;
+
+            case SHA224h:
+                algoId = CTC_SHA224wECDSA;
+                break;
+
+            case SHA256h:
+                algoId = CTC_SHA256wECDSA;
+                break;
+
+            case SHA384h:
+                algoId = CTC_SHA384wECDSA;
+                break;
+
+            case SHA512h:
+                algoId = CTC_SHA512wECDSA;
+                break;
+        }
+    }
+
+    if (algoId == 0) {
+        WOLFSSL_MSG("Invalid signature algorithm type");
+        return BAD_FUNC_ARG;
+    }
+
+    *digEncAlgoId = algoId;
+    *digEncAlgoType = algoType;
+
+    return 0;
+}
+
+
+/* build SignedData DigestInfo for use with PKCS#7/RSA
+ *
+ * pkcs7 - pointer to initialized PKCS7 struct
+ * flatSignedAttribs - flattened, signed attributes
+ * flatSignedAttrbsSz - size of flatSignedAttribs, octets
+ * esd - pointer to initialized ESD struct
+ * digestInfo - [OUT] output array for DigestInfo
+ * digestInfoSz - [IN/OUT] - input size of array, size of digestInfo
+ *
+ * return 0 on success, negative on error */
+static int wc_PKCS7_BuildDigestInfo(PKCS7* pkcs7, byte* flatSignedAttribs,
+                                    word32 flatSignedAttribsSz, ESD* esd,
+                                    byte* digestInfo, word32* digestInfoSz)
+{
+    int ret, hashSz, digIdx = 0;
+    byte digestInfoSeq[MAX_SEQ_SZ];
+    byte digestStr[MAX_OCTET_STR_SZ];
+    byte attribSet[MAX_SET_SZ];
+    byte algoId[MAX_ALGO_SZ];
+    word32 digestInfoSeqSz, digestStrSz, algoIdSz;
+    word32 attribSetSz;
+
+    if (pkcs7 == NULL || esd == NULL || digestInfo == NULL ||
+        digestInfoSz == NULL) {
+        return BAD_FUNC_ARG;
+    }
+
+    hashSz = wc_HashGetDigestSize(esd->hashType);
+    if (hashSz < 0)
+        return hashSz;
+
+    if (pkcs7->signedAttribsSz != 0) {
+
+        if (flatSignedAttribs == NULL)
+            return BAD_FUNC_ARG;
+
+        attribSetSz = SetSet(flatSignedAttribsSz, attribSet);
+
+        ret = wc_HashInit(&esd->hash, esd->hashType);
+        if (ret < 0)
+            return ret;
+
+        ret = wc_HashUpdate(&esd->hash, esd->hashType,
+                            attribSet, attribSetSz);
+        if (ret < 0)
+            return ret;
+
+        ret = wc_HashUpdate(&esd->hash, esd->hashType,
+                            flatSignedAttribs, flatSignedAttribsSz);
+        if (ret < 0)
+            return ret;
+
+        ret = wc_HashFinal(&esd->hash, esd->hashType,
+                           esd->contentAttribsDigest);
+        if (ret < 0)
+            return ret;
+
+    } else {
+        /* when no attrs, digest is contentDigest without tag and length */
+        XMEMCPY(esd->contentAttribsDigest, esd->contentDigest + 2, hashSz);
+    }
+
+    /* set algoID, with NULL attributes */
+    algoIdSz = SetAlgoID(pkcs7->hashOID, algoId, oidHashType, 0);
+
+    digestStrSz = SetOctetString(hashSz, digestStr);
+    digestInfoSeqSz = SetSequence(algoIdSz + digestStrSz + hashSz,
+                                  digestInfoSeq);
+
+    if (*digestInfoSz < (digestInfoSeqSz + algoIdSz + digestStrSz + hashSz)) {
+        return BUFFER_E;
+    }
+
+    XMEMCPY(digestInfo + digIdx, digestInfoSeq, digestInfoSeqSz);
+    digIdx += digestInfoSeqSz;
+    XMEMCPY(digestInfo + digIdx, algoId, algoIdSz);
+    digIdx += algoIdSz;
+    XMEMCPY(digestInfo + digIdx, digestStr, digestStrSz);
+    digIdx += digestStrSz;
+    XMEMCPY(digestInfo + digIdx, esd->contentAttribsDigest, hashSz);
+    digIdx += hashSz;
+
+    *digestInfoSz = digIdx;
+
+    return 0;
+}
+
+
+/* build SignedData signature over DigestInfo or content digest
+ *
+ * pkcs7 - pointer to initizlied PKCS7 struct
+ * flatSignedAttribs - flattened, signed attributes
+ * flatSignedAttribsSz - size of flatSignedAttribs, octets
+ * esd - pointer to initialized ESD struct
+ *
+ * returns length of signature on success, negative on error */
+static int wc_PKCS7_SignedDataBuildSignature(PKCS7* pkcs7,
+                                             byte* flatSignedAttribs,
+                                             word32 flatSignedAttribsSz,
+                                             ESD* esd)
+{
+    int ret;
+#ifdef HAVE_ECC
+    int hashSz;
+#endif
+    word32 digestInfoSz = MAX_PKCS7_DIGEST_SZ;
+#ifdef WOLFSSL_SMALL_STACK
+    byte* digestInfo;
+#else
+    byte digestInfo[MAX_PKCS7_DIGEST_SZ];
+#endif
+
+    if (pkcs7 == NULL || esd == NULL)
+        return BAD_FUNC_ARG;
+
+#ifdef WOLFSSL_SMALL_STACK
+    digestInfo = (byte*)XMALLOC(digestInfoSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (digestInfo == NULL) {
+        return MEMORY_E;
+    }
+#endif
+
+    ret = wc_PKCS7_BuildDigestInfo(pkcs7, flatSignedAttribs,
+                                   flatSignedAttribsSz, esd, digestInfo,
+                                   &digestInfoSz);
+    if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    /* sign digestInfo */
+    switch (pkcs7->publicKeyOID) {
+
+#ifndef NO_RSA
+        case RSAk:
+            ret = wc_PKCS7_RsaSign(pkcs7, digestInfo, digestInfoSz, esd);
+            break;
+#endif
+
+#ifdef HAVE_ECC
+        case ECDSAk:
+            /* CMS with ECDSA does not sign DigestInfo structure
+             * like PKCS#7 with RSA does */
+            hashSz = wc_HashGetDigestSize(esd->hashType);
+            if (hashSz < 0) {
+            #ifdef WOLFSSL_SMALL_STACK
+                XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+            #endif
+                return hashSz;
+            }
+
+            ret = wc_PKCS7_EcdsaSign(pkcs7, esd->contentAttribsDigest,
+                                     hashSz, esd);
+            break;
+#endif
+
+        default:
+            WOLFSSL_MSG("Unsupported public key type");
+            ret = BAD_FUNC_ARG;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    if (ret >= 0) {
+        esd->encContentDigestSz = (word32)ret;
+    }
+
+    return ret;
+}
+
+
+/* sets the wc_HashType in ESD struct based on pkcs7->hashOID
+ *
+ * pkcs7 - pointer to initialized PKCS7 struct
+ * type  - [OUT] pointer to wc_HashType for output
+ *
+ * returns hash digest size on success, negative on error */
+static int wc_PKCS7_SetHashType(PKCS7* pkcs7, enum wc_HashType* type)
+{
+    if (pkcs7 == NULL || type == NULL)
+        return BAD_FUNC_ARG;
+
+    switch (pkcs7->hashOID) {
+
+#ifndef NO_SHA
+        case SHAh:
+            *type = WC_HASH_TYPE_SHA;
+            break;
+#endif
+#ifdef WOLFSSL_SHA224
+        case SHA224h:
+            *type = WC_HASH_TYPE_SHA224;
+            break;
+#endif
+#ifndef NO_SHA256
+        case SHA256h:
+            *type = WC_HASH_TYPE_SHA256;
+            break;
+#endif
+#ifdef WOLFSSL_SHA384
+        case SHA384h:
+            *type = WC_HASH_TYPE_SHA384;
+            break;
+#endif
+#ifdef WOLFSSL_SHA512
+        case SHA512h:
+            *type = WC_HASH_TYPE_SHA512;
+            break;
+#endif
+        default:
+            return BAD_FUNC_ARG;
+    }
+
+    return wc_HashGetDigestSize(*type);
+}
+
+
+/* build PKCS#7 signedData content type */
+int wc_PKCS7_EncodeSignedData(PKCS7* pkcs7, byte* output, word32 outputSz)
+{
+    static const byte outerOid[] =
+        { ASN_OBJECT_ID, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01,
+                         0x07, 0x02 };
+    static const byte innerOid[] =
+        { ASN_OBJECT_ID, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01,
+                         0x07, 0x01 };
+
+    byte contentTypeOid[] =
+            { ASN_OBJECT_ID, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xF7, 0x0d, 0x01,
+                             0x09, 0x03 };
+    byte contentType[] =
+            { ASN_OBJECT_ID, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01,
+                             0x07, 0x01 };
+    byte messageDigestOid[] =
+            { ASN_OBJECT_ID, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01,
+                             0x09, 0x04 };
+
+#ifdef WOLFSSL_SMALL_STACK
+    ESD* esd = NULL;
+#else
+    ESD stack_esd;
+    ESD* esd = &stack_esd;
+#endif
+
+    word32 signerInfoSz = 0;
+    word32 totalSz = 0;
+    int idx = 0, ret = 0;
+    int digEncAlgoId, digEncAlgoType, hashSz;
+    byte* flatSignedAttribs = NULL;
+    word32 flatSignedAttribsSz = 0;
+    word32 innerOidSz = sizeof(innerOid);
+    word32 outerOidSz = sizeof(outerOid);
+
+    if (pkcs7 == NULL || pkcs7->content == NULL || pkcs7->contentSz == 0 ||
+        pkcs7->encryptOID == 0 || pkcs7->hashOID == 0 || pkcs7->rng == 0 ||
+        pkcs7->singleCert == NULL || pkcs7->singleCertSz == 0 ||
+        pkcs7->privateKey == NULL || pkcs7->privateKeySz == 0 ||
+        output == NULL || outputSz == 0)
+        return BAD_FUNC_ARG;
+
+#ifdef WOLFSSL_SMALL_STACK
+    esd = (ESD*)XMALLOC(sizeof(ESD), NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (esd == NULL)
+        return MEMORY_E;
+#endif
+
+    XMEMSET(esd, 0, sizeof(ESD));
+
+    hashSz = wc_PKCS7_SetHashType(pkcs7, &esd->hashType);
+    if (hashSz < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return hashSz;
+    }
+
+    ret = wc_HashInit(&esd->hash, esd->hashType);
+    if (ret != 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    if (pkcs7->contentSz != 0)
+    {
+        ret = wc_HashUpdate(&esd->hash, esd->hashType,
+                            pkcs7->content, pkcs7->contentSz);
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+        }
+        esd->contentDigest[0] = ASN_OCTET_STRING;
+        esd->contentDigest[1] = (byte)hashSz;
+        ret = wc_HashFinal(&esd->hash, esd->hashType,
+                           &esd->contentDigest[2]);
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+        }
+    }
+
+    esd->innerOctetsSz = SetOctetString(pkcs7->contentSz, esd->innerOctets);
+    esd->innerContSeqSz = SetExplicit(0, esd->innerOctetsSz + pkcs7->contentSz,
+                                esd->innerContSeq);
+    esd->contentInfoSeqSz = SetSequence(pkcs7->contentSz + esd->innerOctetsSz +
+                                    innerOidSz + esd->innerContSeqSz,
+                                    esd->contentInfoSeq);
+
+    esd->issuerSnSz = SetSerialNumber(pkcs7->issuerSn, pkcs7->issuerSnSz,
+                                     esd->issuerSn);
+    signerInfoSz += esd->issuerSnSz;
+    esd->issuerNameSz = SetSequence(pkcs7->issuerSz, esd->issuerName);
+    signerInfoSz += esd->issuerNameSz + pkcs7->issuerSz;
+    esd->issuerSnSeqSz = SetSequence(signerInfoSz, esd->issuerSnSeq);
+    signerInfoSz += esd->issuerSnSeqSz;
+    esd->signerVersionSz = SetMyVersion(1, esd->signerVersion, 0);
+    signerInfoSz += esd->signerVersionSz;
+    esd->signerDigAlgoIdSz = SetAlgoID(pkcs7->hashOID, esd->signerDigAlgoId,
+                                      oidHashType, 0);
+    signerInfoSz += esd->signerDigAlgoIdSz;
+
+    /* set signatureAlgorithm */
+    ret = wc_PKCS7_SignedDataGetEncAlgoId(pkcs7, &digEncAlgoId,
+                                          &digEncAlgoType);
+    if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+    esd->digEncAlgoIdSz = SetAlgoID(digEncAlgoId, esd->digEncAlgoId,
+                                    digEncAlgoType, 0);
+    signerInfoSz += esd->digEncAlgoIdSz;
+
+    if (pkcs7->signedAttribsSz != 0) {
+
+        /* build up signed attributes */
+        ret = wc_PKCS7_BuildSignedAttributes(pkcs7, esd,
+                                    contentTypeOid, sizeof(contentTypeOid),
+                                    contentType, sizeof(contentType),
+                                    messageDigestOid, sizeof(messageDigestOid));
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return MEMORY_E;
+        }
+
+        flatSignedAttribs = (byte*)XMALLOC(esd->signedAttribsSz, pkcs7->heap,
+                                                         DYNAMIC_TYPE_PKCS7);
+        flatSignedAttribsSz = esd->signedAttribsSz;
+        if (flatSignedAttribs == NULL) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return MEMORY_E;
+        }
+
+        FlattenAttributes(flatSignedAttribs,
+                                   esd->signedAttribs, esd->signedAttribsCount);
+        esd->signedAttribSetSz = SetImplicit(ASN_SET, 0, esd->signedAttribsSz,
+                                                          esd->signedAttribSet);
+    }
+
+    /* Calculate the final hash and encrypt it. */
+    ret = wc_PKCS7_SignedDataBuildSignature(pkcs7, flatSignedAttribs,
+                                            flatSignedAttribsSz, esd);
+    if (ret < 0) {
+        if (pkcs7->signedAttribsSz != 0)
+            XFREE(flatSignedAttribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    signerInfoSz += flatSignedAttribsSz + esd->signedAttribSetSz;
+
+    esd->signerDigestSz = SetOctetString(esd->encContentDigestSz,
+                                                             esd->signerDigest);
+    signerInfoSz += esd->signerDigestSz + esd->encContentDigestSz;
+
+    esd->signerInfoSeqSz = SetSequence(signerInfoSz, esd->signerInfoSeq);
+    signerInfoSz += esd->signerInfoSeqSz;
+    esd->signerInfoSetSz = SetSet(signerInfoSz, esd->signerInfoSet);
+    signerInfoSz += esd->signerInfoSetSz;
+
+    esd->certsSetSz = SetImplicit(ASN_SET, 0, pkcs7->singleCertSz,
+                                                                 esd->certsSet);
+
+    esd->singleDigAlgoIdSz = SetAlgoID(pkcs7->hashOID, esd->singleDigAlgoId,
+                                      oidHashType, 0);
+    esd->digAlgoIdSetSz = SetSet(esd->singleDigAlgoIdSz, esd->digAlgoIdSet);
+
+
+    esd->versionSz = SetMyVersion(1, esd->version, 0);
+
+    totalSz = esd->versionSz + esd->singleDigAlgoIdSz + esd->digAlgoIdSetSz +
+              esd->contentInfoSeqSz + esd->certsSetSz + pkcs7->singleCertSz +
+              esd->innerOctetsSz + esd->innerContSeqSz +
+              innerOidSz + pkcs7->contentSz +
+              signerInfoSz;
+    esd->innerSeqSz = SetSequence(totalSz, esd->innerSeq);
+    totalSz += esd->innerSeqSz;
+    esd->outerContentSz = SetExplicit(0, totalSz, esd->outerContent);
+    totalSz += esd->outerContentSz + outerOidSz;
+    esd->outerSeqSz = SetSequence(totalSz, esd->outerSeq);
+    totalSz += esd->outerSeqSz;
+
+    if (outputSz < totalSz) {
+        if (pkcs7->signedAttribsSz != 0)
+            XFREE(flatSignedAttribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return BUFFER_E;
+    }
+
+    idx = 0;
+    XMEMCPY(output + idx, esd->outerSeq, esd->outerSeqSz);
+    idx += esd->outerSeqSz;
+    XMEMCPY(output + idx, outerOid, outerOidSz);
+    idx += outerOidSz;
+    XMEMCPY(output + idx, esd->outerContent, esd->outerContentSz);
+    idx += esd->outerContentSz;
+    XMEMCPY(output + idx, esd->innerSeq, esd->innerSeqSz);
+    idx += esd->innerSeqSz;
+    XMEMCPY(output + idx, esd->version, esd->versionSz);
+    idx += esd->versionSz;
+    XMEMCPY(output + idx, esd->digAlgoIdSet, esd->digAlgoIdSetSz);
+    idx += esd->digAlgoIdSetSz;
+    XMEMCPY(output + idx, esd->singleDigAlgoId, esd->singleDigAlgoIdSz);
+    idx += esd->singleDigAlgoIdSz;
+    XMEMCPY(output + idx, esd->contentInfoSeq, esd->contentInfoSeqSz);
+    idx += esd->contentInfoSeqSz;
+    XMEMCPY(output + idx, innerOid, innerOidSz);
+    idx += innerOidSz;
+    XMEMCPY(output + idx, esd->innerContSeq, esd->innerContSeqSz);
+    idx += esd->innerContSeqSz;
+    XMEMCPY(output + idx, esd->innerOctets, esd->innerOctetsSz);
+    idx += esd->innerOctetsSz;
+    XMEMCPY(output + idx, pkcs7->content, pkcs7->contentSz);
+    idx += pkcs7->contentSz;
+    XMEMCPY(output + idx, esd->certsSet, esd->certsSetSz);
+    idx += esd->certsSetSz;
+    XMEMCPY(output + idx, pkcs7->singleCert, pkcs7->singleCertSz);
+    idx += pkcs7->singleCertSz;
+    XMEMCPY(output + idx, esd->signerInfoSet, esd->signerInfoSetSz);
+    idx += esd->signerInfoSetSz;
+    XMEMCPY(output + idx, esd->signerInfoSeq, esd->signerInfoSeqSz);
+    idx += esd->signerInfoSeqSz;
+    XMEMCPY(output + idx, esd->signerVersion, esd->signerVersionSz);
+    idx += esd->signerVersionSz;
+    XMEMCPY(output + idx, esd->issuerSnSeq, esd->issuerSnSeqSz);
+    idx += esd->issuerSnSeqSz;
+    XMEMCPY(output + idx, esd->issuerName, esd->issuerNameSz);
+    idx += esd->issuerNameSz;
+    XMEMCPY(output + idx, pkcs7->issuer, pkcs7->issuerSz);
+    idx += pkcs7->issuerSz;
+    XMEMCPY(output + idx, esd->issuerSn, esd->issuerSnSz);
+    idx += esd->issuerSnSz;
+    XMEMCPY(output + idx, esd->signerDigAlgoId, esd->signerDigAlgoIdSz);
+    idx += esd->signerDigAlgoIdSz;
+
+    /* SignerInfo:Attributes */
+    if (flatSignedAttribsSz > 0) {
+        XMEMCPY(output + idx, esd->signedAttribSet, esd->signedAttribSetSz);
+        idx += esd->signedAttribSetSz;
+        XMEMCPY(output + idx, flatSignedAttribs, flatSignedAttribsSz);
+        idx += flatSignedAttribsSz;
+        XFREE(flatSignedAttribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+    }
+
+    XMEMCPY(output + idx, esd->digEncAlgoId, esd->digEncAlgoIdSz);
+    idx += esd->digEncAlgoIdSz;
+    XMEMCPY(output + idx, esd->signerDigest, esd->signerDigestSz);
+    idx += esd->signerDigestSz;
+    XMEMCPY(output + idx, esd->encContentDigest, esd->encContentDigestSz);
+    idx += esd->encContentDigestSz;
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(esd, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return idx;
+}
+
+
+#ifndef NO_RSA
+
+/* returns size of signature put into out, negative on error */
+static int wc_PKCS7_RsaVerify(PKCS7* pkcs7, byte* sig, int sigSz,
+                              byte* hash, word32 hashSz)
+{
+    int ret = 0;
+    word32 scratch = 0;
+#ifdef WOLFSSL_SMALL_STACK
+    byte* digest;
+    RsaKey* key;
+#else
+    byte digest[MAX_PKCS7_DIGEST_SZ];
+    RsaKey stack_key;
+    RsaKey* key = &stack_key;
+#endif
+
+    if (pkcs7 == NULL || sig == NULL || hash == NULL) {
+        return BAD_FUNC_ARG;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    digest = (byte*)XMALLOC(MAX_PKCS7_DIGEST_SZ, NULL,
+                            DYNAMIC_TYPE_TMP_BUFFER);
+
+    if (digest == NULL)
+        return MEMORY_E;
+
+    key = (RsaKey*)XMALLOC(sizeof(RsaKey), NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (key == NULL) {
+        XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        return MEMORY_E;
+    }
+#endif
+
+    XMEMSET(digest, 0, MAX_PKCS7_DIGEST_SZ);
+
+    ret = wc_InitRsaKey(key, pkcs7->heap);
+    if (ret != 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(key,    NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    if (wc_RsaPublicKeyDecode(pkcs7->publicKey, &scratch, key,
+                              pkcs7->publicKeySz) < 0) {
+        WOLFSSL_MSG("ASN RSA key decode error");
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(key,    NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return PUBLIC_KEY_E;
+    }
+
+    ret = wc_RsaSSL_Verify(sig, sigSz, digest, MAX_PKCS7_DIGEST_SZ, key);
+
+    wc_FreeRsaKey(key);
+
+    if (((int)hashSz != ret) || (XMEMCMP(digest, hash, ret) != 0)) {
+        ret = SIG_VERIFY_E;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    XFREE(key,    NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return ret;
+}
+
+#endif /* NO_RSA */
+
+
+#ifdef HAVE_ECC
+
+/* returns size of signature put into out, negative on error */
+static int wc_PKCS7_EcdsaVerify(PKCS7* pkcs7, byte* sig, int sigSz,
+                                byte* hash, word32 hashSz)
+{
+    int ret = 0;
+    int res = 0;
+#ifdef WOLFSSL_SMALL_STACK
+    byte* digest;
+    ecc_key* key;
+#else
+    byte digest[MAX_PKCS7_DIGEST_SZ];
+    ecc_key stack_key;
+    ecc_key* key = &stack_key;
+#endif
+
+    if (pkcs7 == NULL || sig == NULL)
+        return BAD_FUNC_ARG;
+
+#ifdef WOLFSSL_SMALL_STACK
+    digest = (byte*)XMALLOC(MAX_PKCS7_DIGEST_SZ, NULL,
+                            DYNAMIC_TYPE_TMP_BUFFER);
+
+    if (digest == NULL)
+        return MEMORY_E;
+
+    key = (ecc_key*)XMALLOC(sizeof(ecc_key), NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (key == NULL) {
+        XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        return MEMORY_E;
+    }
+#endif
+
+    XMEMSET(digest, 0, MAX_PKCS7_DIGEST_SZ);
+
+    ret = wc_ecc_init_ex(key, pkcs7->heap, INVALID_DEVID);
+    if (ret != 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(key,    NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    if (wc_ecc_import_x963(pkcs7->publicKey, pkcs7->publicKeySz, key) < 0) {
+        WOLFSSL_MSG("ASN ECDSA key decode error");
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(key,    NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return PUBLIC_KEY_E;
+    }
+
+    ret = wc_ecc_verify_hash(sig, sigSz, hash, hashSz, &res, key);
+
+    wc_ecc_free(key);
+
+    if (ret == 0 && res != 1) {
+        ret = SIG_VERIFY_E;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    XFREE(key,    NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return ret;
+}
+
+#endif /* HAVE_ECC */
+
+
+/* build SignedData digest, both in PKCS#7 DigestInfo format and
+ * as plain digest for CMS.
+ *
+ * pkcs7          - pointer to initialized PKCS7 struct
+ * signedAttrib   - signed attributes
+ * signedAttribSz - size of signedAttrib, octets
+ * pkcs7Digest    - [OUT] PKCS#7 DigestInfo
+ * pkcs7DigestSz  - [IN/OUT] size of pkcs7Digest
+ * plainDigest    - [OUT] pointer to plain digest, offset into pkcs7Digest
+ * plainDigestSz  - [OUT] size of digest at plainDigest
+ *
+ * returns 0 on success, negative on error */
+static int wc_PKCS7_BuildSignedDataDigest(PKCS7* pkcs7, byte* signedAttrib,
+                                      word32 signedAttribSz, byte* pkcs7Digest,
+                                      word32* pkcs7DigestSz, byte** plainDigest,
+                                      word32* plainDigestSz)
+{
+    int ret = 0, digIdx = 0, hashSz;
+    word32 attribSetSz;
+    byte attribSet[MAX_SET_SZ];
+    byte digest[WC_MAX_DIGEST_SIZE];
+    byte digestInfoSeq[MAX_SEQ_SZ];
+    byte digestStr[MAX_OCTET_STR_SZ];
+    byte algoId[MAX_ALGO_SZ];
+    word32 digestInfoSeqSz, digestStrSz, algoIdSz;
+#ifdef WOLFSSL_SMALL_STACK
+    byte* digestInfo;
+#else
+    byte digestInfo[MAX_PKCS7_DIGEST_SZ];
+#endif
+
+    wc_HashAlg hash;
+    enum wc_HashType hashType;
+
+    if (pkcs7 == NULL || pkcs7Digest == NULL ||
+        pkcs7DigestSz == NULL || plainDigest == NULL) {
+        return BAD_FUNC_ARG;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    digestInfo = (byte*)XMALLOC(MAX_PKCS7_DIGEST_SZ, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (digestInfo == NULL)
+        return MEMORY_E;
+#endif
+
+    XMEMSET(pkcs7Digest, 0, *pkcs7DigestSz);
+    XMEMSET(digest,      0, WC_MAX_DIGEST_SIZE);
+    XMEMSET(digestInfo,  0, MAX_PKCS7_DIGEST_SZ);
+
+    hashSz = wc_PKCS7_SetHashType(pkcs7, &hashType);
+    if (hashSz < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return hashSz;
+    }
+
+    /* calculate digest */
+    ret = wc_HashInit(&hash, hashType);
+    if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    if (signedAttribSz > 0) {
+
+        if (signedAttrib == NULL) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return BAD_FUNC_ARG;
+        }
+
+        attribSetSz = SetSet(signedAttribSz, attribSet);
+        ret = wc_HashUpdate(&hash, hashType, attribSet, attribSetSz);
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return ret;
+        }
+
+        ret = wc_HashUpdate(&hash, hashType, signedAttrib, signedAttribSz);
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return ret;
+        }
+
+        ret = wc_HashFinal(&hash, hashType, digest);
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return ret;
+        }
+
+    } else {
+
+        if (pkcs7->content == NULL) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return BAD_FUNC_ARG;
+        }
+
+        ret = wc_HashUpdate(&hash, hashType, pkcs7->content, pkcs7->contentSz);
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return ret;
+        }
+
+        ret = wc_HashFinal(&hash, hashType, digest);
+        if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+            XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+            return ret;
+        }
+    }
+
+    /* Set algoID, with NULL attributes */
+    algoIdSz = SetAlgoID(pkcs7->hashOID, algoId, oidHashType, 0);
+
+    digestStrSz = SetOctetString(hashSz, digestStr);
+    digestInfoSeqSz = SetSequence(algoIdSz + digestStrSz + hashSz,
+                                  digestInfoSeq);
+
+    XMEMCPY(digestInfo + digIdx, digestInfoSeq, digestInfoSeqSz);
+    digIdx += digestInfoSeqSz;
+    XMEMCPY(digestInfo + digIdx, algoId, algoIdSz);
+    digIdx += algoIdSz;
+    XMEMCPY(digestInfo + digIdx, digestStr, digestStrSz);
+    digIdx += digestStrSz;
+    XMEMCPY(digestInfo + digIdx, digest, hashSz);
+    digIdx += hashSz;
+
+    XMEMCPY(pkcs7Digest, digestInfo, digIdx);
+    *pkcs7DigestSz = digIdx;
+
+    /* set plain digest pointer */
+    *plainDigest = pkcs7Digest + digIdx - hashSz;
+    *plainDigestSz = hashSz;
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(digestInfo, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+    return 0;
+}
+
+
+/* verifies SignedData signature, over either PKCS#7 DigestInfo or
+ * content digest.
+ *
+ * pkcs7          - pointer to initialized PKCS7 struct
+ * sig            - signature to verify
+ * sigSz          - size of sig
+ * signedAttrib   - signed attributes, or null if empty
+ * signedAttribSz - size of signedAttributes
+ *
+ * return 0 on success, negative on error */
+static int wc_PKCS7_SignedDataVerifySignature(PKCS7* pkcs7, byte* sig,
+                                              word32 sigSz, byte* signedAttrib,
+                                              word32 signedAttribSz)
+{
+    int ret = 0;
+    word32 plainDigestSz = 0, pkcs7DigestSz;
+    byte* plainDigest = NULL; /* offset into pkcs7Digest */
+#ifdef WOLFSSL_SMALL_STACK
+    byte* pkcs7Digest;
+#else
+    byte  pkcs7Digest[MAX_PKCS7_DIGEST_SZ];
+#endif
+
+    if (pkcs7 == NULL)
+        return BAD_FUNC_ARG;
+
+#ifdef WOLFSSL_SMALL_STACK
+    pkcs7Digest = (byte*)XMALLOC(MAX_PKCS7_DIGEST_SZ, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (pkcs7Digest == NULL)
+        return MEMORY_E;
+#endif
+
+    /* build hash to verify against */
+    pkcs7DigestSz = MAX_PKCS7_DIGEST_SZ;
+    ret = wc_PKCS7_BuildSignedDataDigest(pkcs7, signedAttrib,
+                                         signedAttribSz, pkcs7Digest,
+                                         &pkcs7DigestSz, &plainDigest,
+                                         &plainDigestSz);
+    if (ret < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(pkcs7Digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    switch (pkcs7->publicKeyOID) {
+
+#ifndef NO_RSA
+        case RSAk:
+            ret = wc_PKCS7_RsaVerify(pkcs7, sig, sigSz, pkcs7Digest,
+                                     pkcs7DigestSz);
+            if (ret < 0) {
+                WOLFSSL_MSG("PKCS#7 verification failed, trying CMS");
+                ret = wc_PKCS7_RsaVerify(pkcs7, sig, sigSz, plainDigest,
+                                         plainDigestSz);
+            }
+            break;
+#endif
+
+#ifdef HAVE_ECC
+        case ECDSAk:
+            ret = wc_PKCS7_EcdsaVerify(pkcs7, sig, sigSz, plainDigest,
+                                       plainDigestSz);
+            break;
+#endif
+
+        default:
+            WOLFSSL_MSG("Unsupported public key type");
+            ret = BAD_FUNC_ARG;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+     XFREE(pkcs7Digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+    return ret;
+}
+
+
+/* Finds the certificates in the message and saves it. */
+int wc_PKCS7_VerifySignedData(PKCS7* pkcs7, byte* pkiMsg, word32 pkiMsgSz)
+{
+    word32 idx, contentType, hashOID;
+    int length, version, ret;
+    byte* content = NULL;
+    byte* sig = NULL;
+    byte* cert = NULL;
+    byte* signedAttrib = NULL;
+    int contentSz = 0, sigSz = 0, certSz = 0, signedAttribSz = 0;
+
+    if (pkcs7 == NULL || pkiMsg == NULL || pkiMsgSz == 0)
+        return BAD_FUNC_ARG;
+
+    idx = 0;
+
+    /* Get the contentInfo sequence */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* Get the contentInfo contentType */
+    if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (contentType != SIGNED_DATA) {
+        WOLFSSL_MSG("PKCS#7 input not of type SignedData");
+        return PKCS7_OID_E;
+    }
+
+    /* get the ContentInfo content */
+    if (pkiMsg[idx++] != (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0))
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* Get the signedData sequence */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* Get the version */
+    if (GetMyVersion(pkiMsg, &idx, &version, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (version != 1) {
+        WOLFSSL_MSG("PKCS#7 signedData needs to be of version 1");
+        return ASN_VERSION_E;
+    }
+
+    /* Get the set of DigestAlgorithmIdentifiers */
+    if (GetSet(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* Skip the set. */
+    idx += length;
+
+    /* Get the inner ContentInfo sequence */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* Get the inner ContentInfo contentType */
+    if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (contentType != DATA) {
+        WOLFSSL_MSG("PKCS#7 inner input not of type Data");
+        return PKCS7_OID_E;
+    }
+
+    if (pkiMsg[idx++] != (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0))
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) <= 0)
+        return ASN_PARSE_E;
+
+    if (pkiMsg[idx++] != ASN_OCTET_STRING)
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* Save the inner data as the content. */
+    if (length > 0) {
+        /* Local pointer for calculating hashes later */
+        pkcs7->content = content = &pkiMsg[idx];
+        pkcs7->contentSz = contentSz = length;
+        idx += length;
+    }
+
+    /* Get the implicit[0] set of certificates */
+    if (pkiMsg[idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0)) {
+        idx++;
+        if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+        if (length > 0) {
+            /* At this point, idx is at the first certificate in
+             * a set of certificates. There may be more than one,
+             * or none, or they may be a PKCS 6 extended
+             * certificate. We want to save the first cert if it
+             * is X.509. */
+
+            word32 certIdx = idx;
+
+            if (pkiMsg[certIdx++] == (ASN_CONSTRUCTED | ASN_SEQUENCE)) {
+                if (GetLength(pkiMsg, &certIdx, &certSz, pkiMsgSz) < 0)
+                    return ASN_PARSE_E;
+
+                cert = &pkiMsg[idx];
+                certSz += (certIdx - idx);
+            }
+            wc_PKCS7_InitWithCert(pkcs7, cert, certSz);
+        }
+        idx += length;
+    }
+
+    /* Get the implicit[1] set of crls */
+    if (pkiMsg[idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 1)) {
+        idx++;
+        if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+        /* Skip the set */
+        idx += length;
+    }
+
+    /* Get the set of signerInfos */
+    if (GetSet(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (length > 0) {
+        /* Get the sequence of the first signerInfo */
+        if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+        /* Get the version */
+        if (GetMyVersion(pkiMsg, &idx, &version, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+        if (version != 1) {
+            WOLFSSL_MSG("PKCS#7 signerInfo needs to be of version 1");
+            return ASN_VERSION_E;
+        }
+
+        /* Get the sequence of IssuerAndSerialNumber */
+        if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+        /* Skip it */
+        idx += length;
+
+        /* Get the sequence of digestAlgorithm */
+        if (GetAlgoId(pkiMsg, &idx, &hashOID, oidHashType, pkiMsgSz) < 0) {
+            return ASN_PARSE_E;
+        }
+        pkcs7->hashOID = (int)hashOID;
+
+        /* Get the IMPLICIT[0] SET OF signedAttributes */
+        if (pkiMsg[idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0)) {
+            idx++;
+
+            if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+                return ASN_PARSE_E;
+
+            /* save pointer and length */
+            signedAttrib = &pkiMsg[idx];
+            signedAttribSz = length;
+
+            idx += length;
+        }
+
+        /* Get the sequence of digestEncryptionAlgorithm */
+        if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+        /* Skip it */
+        idx += length;
+
+        /* Get the signature */
+        if (pkiMsg[idx] == ASN_OCTET_STRING) {
+            idx++;
+
+            if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+                return ASN_PARSE_E;
+
+            /* save pointer and length */
+            sig = &pkiMsg[idx];
+            sigSz = length;
+
+            idx += length;
+        }
+
+        pkcs7->content = content;
+        pkcs7->contentSz = contentSz;
+
+        ret = wc_PKCS7_SignedDataVerifySignature(pkcs7, sig, sigSz,
+                                                 signedAttrib, signedAttribSz);
+        if (ret < 0)
+            return ret;
+    }
+
+    return 0;
+}
+
+
+#ifdef HAVE_ECC
+
+/* KARI == KeyAgreeRecipientInfo (key agreement) */
+typedef struct WC_PKCS7_KARI {
+    DecodedCert* decoded;          /* decoded recip cert */
+    void*    heap;                 /* user heap, points to PKCS7->heap */
+    ecc_key* recipKey;             /* recip key  (pub | priv) */
+    ecc_key* senderKey;            /* sender key (pub | priv) */
+    byte*    senderKeyExport;      /* sender ephemeral key DER */
+    byte*    kek;                  /* key encryption key */
+    byte*    ukm;                  /* OPTIONAL user keying material */
+    byte*    sharedInfo;           /* ECC-CMS-SharedInfo ASN.1 encoded blob */
+    word32   senderKeyExportSz;    /* size of sender ephemeral key DER */
+    word32   kekSz;                /* size of key encryption key */
+    word32   ukmSz;                /* size of user keying material */
+    word32   sharedInfoSz;         /* size of ECC-CMS-SharedInfo encoded */
+    byte     ukmOwner;             /* do we own ukm buffer? 1:yes, 0:no */
+    byte     direction;            /* WC_PKCS7_ENCODE | WC_PKCS7_DECODE */
+} WC_PKCS7_KARI;
+
+
+/* wrap CEK (content encryption key) with KEK, 0 on success, < 0 on error */
+static int wc_PKCS7_KariKeyWrap(byte* cek, word32 cekSz, byte* kek,
+                                word32 kekSz, byte* out, word32 outSz,
+                                int keyWrapAlgo, int direction)
+{
+    int ret;
+
+    if (cek == NULL || kek == NULL || out == NULL)
+        return BAD_FUNC_ARG;
+
+    switch (keyWrapAlgo) {
+#ifndef NO_AES
+        case AES128_WRAP:
+        case AES192_WRAP:
+        case AES256_WRAP:
+
+            if (direction == AES_ENCRYPTION) {
+
+                ret = wc_AesKeyWrap(kek, kekSz, cek, cekSz,
+                                    out, outSz, NULL);
+
+            } else if (direction == AES_DECRYPTION) {
+
+                ret = wc_AesKeyUnWrap(kek, kekSz, cek, cekSz,
+                                      out, outSz, NULL);
+            } else {
+                WOLFSSL_MSG("Bad key un/wrap direction");
+                return BAD_FUNC_ARG;
+            }
+
+            if (ret <= 0)
+                return ret;
+
+            break;
+#endif /* NO_AES */
+
+        default:
+            WOLFSSL_MSG("Unsupported key wrap algorithm");
+            return BAD_KEYWRAP_ALG_E;
+    };
+
+    (void)cekSz;
+    (void)kekSz;
+    (void)outSz;
+    (void)direction;
+    return ret;
+}
+
+
+/* allocate and create new WC_PKCS7_KARI struct,
+ * returns struct pointer on success, NULL on failure */
+static WC_PKCS7_KARI* wc_PKCS7_KariNew(PKCS7* pkcs7, byte direction)
+{
+    WC_PKCS7_KARI* kari = NULL;
+
+    if (pkcs7 == NULL)
+        return NULL;
+
+    kari = (WC_PKCS7_KARI*)XMALLOC(sizeof(WC_PKCS7_KARI), pkcs7->heap,
+                                   DYNAMIC_TYPE_PKCS7);
+    if (kari == NULL) {
+        WOLFSSL_MSG("Failed to allocate WC_PKCS7_KARI");
+        return NULL;
+    }
+
+    kari->decoded = (DecodedCert*)XMALLOC(sizeof(DecodedCert), pkcs7->heap,
+                                          DYNAMIC_TYPE_PKCS7);
+    if (kari->decoded == NULL) {
+        WOLFSSL_MSG("Failed to allocate DecodedCert");
+        XFREE(kari, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return NULL;
+    }
+
+    kari->recipKey = (ecc_key*)XMALLOC(sizeof(ecc_key), pkcs7->heap,
+                                       DYNAMIC_TYPE_PKCS7);
+    if (kari->recipKey == NULL) {
+        WOLFSSL_MSG("Failed to allocate recipient ecc_key");
+        XFREE(kari->decoded, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(kari, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return NULL;
+    }
+
+    kari->senderKey = (ecc_key*)XMALLOC(sizeof(ecc_key), pkcs7->heap,
+                                        DYNAMIC_TYPE_PKCS7);
+    if (kari->senderKey == NULL) {
+        WOLFSSL_MSG("Failed to allocate sender ecc_key");
+        XFREE(kari->recipKey, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(kari->decoded, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(kari, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return NULL;
+    }
+
+    kari->senderKeyExport = NULL;
+    kari->senderKeyExportSz = 0;
+    kari->kek = NULL;
+    kari->kekSz = 0;
+    kari->ukm = NULL;
+    kari->ukmSz = 0;
+    kari->ukmOwner = 0;
+    kari->sharedInfo = NULL;
+    kari->sharedInfoSz = 0;
+    kari->direction = direction;
+
+    kari->heap = pkcs7->heap;
+
+    return kari;
+}
+
+
+/* free WC_PKCS7_KARI struct, return 0 on success */
+static int wc_PKCS7_KariFree(WC_PKCS7_KARI* kari)
+{
+    void* heap;
+
+    if (kari) {
+        heap = kari->heap;
+
+        if (kari->decoded) {
+            FreeDecodedCert(kari->decoded);
+            XFREE(kari->decoded, heap, DYNAMIC_TYPE_PKCS7);
+        }
+        if (kari->senderKey) {
+            wc_ecc_free(kari->senderKey);
+            XFREE(kari->senderKey, heap, DYNAMIC_TYPE_PKCS7);
+        }
+        if (kari->recipKey) {
+            wc_ecc_free(kari->recipKey);
+            XFREE(kari->recipKey, heap, DYNAMIC_TYPE_PKCS7);
+        }
+        if (kari->senderKeyExport) {
+            ForceZero(kari->senderKeyExport, kari->senderKeyExportSz);
+            XFREE(kari->senderKeyExport, heap, DYNAMIC_TYPE_PKCS7);
+            kari->senderKeyExportSz = 0;
+        }
+        if (kari->kek) {
+            ForceZero(kari->kek, kari->kekSz);
+            XFREE(kari->kek, heap, DYNAMIC_TYPE_PKCS7);
+            kari->kekSz = 0;
+        }
+        if (kari->ukm) {
+            if (kari->ukmOwner == 1) {
+                XFREE(kari->ukm, heap, DYNAMIC_TYPE_PKCS7);
+            }
+            kari->ukmSz = 0;
+        }
+        if (kari->sharedInfo) {
+            ForceZero(kari->sharedInfo, kari->sharedInfoSz);
+            XFREE(kari->sharedInfo, heap, DYNAMIC_TYPE_PKCS7);
+            kari->sharedInfoSz = 0;
+        }
+        XFREE(kari, heap, DYNAMIC_TYPE_PKCS7);
+    }
+
+    (void)heap;
+
+    return 0;
+}
+
+
+/* parse recipient cert/key, return 0 on success, negative on error
+ * key/keySz only needed during decoding (WC_PKCS7_DECODE) */
+static int wc_PKCS7_KariParseRecipCert(WC_PKCS7_KARI* kari, const byte* cert,
+                                       word32 certSz, const byte* key,
+                                       word32 keySz)
+{
+    int ret;
+    word32 idx;
+
+    if (kari == NULL || kari->decoded == NULL ||
+        cert == NULL || certSz == 0)
+        return BAD_FUNC_ARG;
+
+    if (kari->direction == WC_PKCS7_DECODE &&
+        (key == NULL || keySz == 0))
+        return BAD_FUNC_ARG;
+
+    /* decode certificate */
+    InitDecodedCert(kari->decoded, (byte*)cert, certSz, kari->heap);
+    ret = ParseCert(kari->decoded, CA_TYPE, NO_VERIFY, 0);
+    if (ret < 0)
+        return ret;
+
+    /* make sure subject key id was read from cert */
+    if (kari->decoded->extSubjKeyIdSet == 0) {
+        WOLFSSL_MSG("Failed to read subject key ID from recipient cert");
+        return BAD_FUNC_ARG;
+    }
+
+    ret = wc_ecc_init_ex(kari->recipKey, kari->heap, INVALID_DEVID);
+    if (ret != 0)
+        return ret;
+
+    /* get recip public key */
+    if (kari->direction == WC_PKCS7_ENCODE) {
+
+        ret = wc_ecc_import_x963(kari->decoded->publicKey,
+                                 kari->decoded->pubKeySize,
+                                 kari->recipKey);
+    }
+    /* get recip private key */
+    else if (kari->direction == WC_PKCS7_DECODE) {
+
+        idx = 0;
+        ret = wc_EccPrivateKeyDecode(key, &idx, kari->recipKey, keySz);
+        if (ret != 0)
+            return ret;
+
+    } else {
+        /* bad direction */
+        return BAD_FUNC_ARG;
+    }
+
+    if (ret != 0)
+        return ret;
+
+    (void)idx;
+
+    return 0;
+}
+
+
+/* create ephemeral ECC key, places ecc_key in kari->senderKey,
+ * DER encoded in kari->senderKeyExport. return 0 on success,
+ * negative on error */
+static int wc_PKCS7_KariGenerateEphemeralKey(WC_PKCS7_KARI* kari, WC_RNG* rng)
+{
+    int ret;
+
+    if (kari == NULL || kari->decoded == NULL ||
+        kari->recipKey == NULL || kari->recipKey->dp == NULL ||
+        rng == NULL)
+        return BAD_FUNC_ARG;
+
+    kari->senderKeyExport = (byte*)XMALLOC(kari->decoded->pubKeySize, kari->heap,
+                                           DYNAMIC_TYPE_PKCS7);
+    if (kari->senderKeyExport == NULL)
+        return MEMORY_E;
+
+    kari->senderKeyExportSz = kari->decoded->pubKeySize;
+
+    ret = wc_ecc_init_ex(kari->senderKey, kari->heap, INVALID_DEVID);
+    if (ret != 0)
+        return ret;
+
+    ret = wc_ecc_make_key_ex(rng, kari->recipKey->dp->size,
+                             kari->senderKey, kari->recipKey->dp->id);
+    if (ret != 0)
+        return ret;
+
+    /* dump generated key to X.963 DER for output in CMS bundle */
+    ret = wc_ecc_export_x963(kari->senderKey, kari->senderKeyExport,
+                             &kari->senderKeyExportSz);
+    if (ret != 0)
+        return ret;
+
+    return 0;
+}
+
+
+/* create ASN.1 encoded ECC-CMS-SharedInfo using specified key wrap algorithm,
+ * place in kari->sharedInfo. returns 0 on success, negative on error */
+static int wc_PKCS7_KariGenerateSharedInfo(WC_PKCS7_KARI* kari, int keyWrapOID)
+{
+    int idx = 0;
+    int sharedInfoSeqSz = 0;
+    int keyInfoSz = 0;
+    int suppPubInfoSeqSz = 0;
+    int entityUInfoOctetSz = 0;
+    int entityUInfoExplicitSz = 0;
+    int kekOctetSz = 0;
+    int sharedInfoSz = 0;
+
+    word32 kekBitSz = 0;
+
+    byte sharedInfoSeq[MAX_SEQ_SZ];
+    byte keyInfo[MAX_ALGO_SZ];
+    byte suppPubInfoSeq[MAX_SEQ_SZ];
+    byte entityUInfoOctet[MAX_OCTET_STR_SZ];
+    byte entityUInfoExplicitSeq[MAX_SEQ_SZ];
+    byte kekOctet[MAX_OCTET_STR_SZ];
+
+    if (kari == NULL)
+        return BAD_FUNC_ARG;
+
+    if ((kari->ukmSz > 0) && (kari->ukm == NULL))
+        return BAD_FUNC_ARG;
+
+    /* kekOctet */
+    kekOctetSz = SetOctetString(sizeof(word32), kekOctet);
+    sharedInfoSz += (kekOctetSz + sizeof(word32));
+
+    /* suppPubInfo */
+    suppPubInfoSeqSz = SetImplicit(ASN_SEQUENCE, 2,
+                                   kekOctetSz + sizeof(word32),
+                                   suppPubInfoSeq);
+    sharedInfoSz += suppPubInfoSeqSz;
+
+    /* optional ukm/entityInfo */
+    if (kari->ukmSz > 0) {
+        entityUInfoOctetSz = SetOctetString(kari->ukmSz, entityUInfoOctet);
+        sharedInfoSz += (entityUInfoOctetSz + kari->ukmSz);
+
+        entityUInfoExplicitSz = SetExplicit(0, entityUInfoOctetSz +
+                                            kari->ukmSz,
+                                            entityUInfoExplicitSeq);
+        sharedInfoSz += entityUInfoExplicitSz;
+    }
+
+    /* keyInfo */
+    keyInfoSz = SetAlgoID(keyWrapOID, keyInfo, oidKeyWrapType, 0);
+    sharedInfoSz += keyInfoSz;
+
+    /* sharedInfo */
+    sharedInfoSeqSz = SetSequence(sharedInfoSz, sharedInfoSeq);
+    sharedInfoSz += sharedInfoSeqSz;
+
+    kari->sharedInfo = (byte*)XMALLOC(sharedInfoSz, kari->heap,
+                                      DYNAMIC_TYPE_PKCS7);
+    if (kari->sharedInfo == NULL)
+        return MEMORY_E;
+
+    kari->sharedInfoSz = sharedInfoSz;
+
+    XMEMCPY(kari->sharedInfo + idx, sharedInfoSeq, sharedInfoSeqSz);
+    idx += sharedInfoSeqSz;
+    XMEMCPY(kari->sharedInfo + idx, keyInfo, keyInfoSz);
+    idx += keyInfoSz;
+    if (kari->ukmSz > 0) {
+        XMEMCPY(kari->sharedInfo + idx, entityUInfoExplicitSeq,
+                entityUInfoExplicitSz);
+        idx += entityUInfoExplicitSz;
+        XMEMCPY(kari->sharedInfo + idx, entityUInfoOctet, entityUInfoOctetSz);
+        idx += entityUInfoOctetSz;
+        XMEMCPY(kari->sharedInfo + idx, kari->ukm, kari->ukmSz);
+        idx += kari->ukmSz;
+    }
+    XMEMCPY(kari->sharedInfo + idx, suppPubInfoSeq, suppPubInfoSeqSz);
+    idx += suppPubInfoSeqSz;
+    XMEMCPY(kari->sharedInfo + idx, kekOctet, kekOctetSz);
+    idx += kekOctetSz;
+
+    kekBitSz = (kari->kekSz) * 8;              /* convert to bits */
+#ifdef LITTLE_ENDIAN_ORDER
+    kekBitSz = ByteReverseWord32(kekBitSz);    /* network byte order */
+#endif
+    XMEMCPY(kari->sharedInfo + idx, &kekBitSz, sizeof(kekBitSz));
+
+    return 0;
+}
+
+
+/* create key encryption key (KEK) using key wrap algorithm and key encryption
+ * algorithm, place in kari->kek. return 0 on success, <0 on error. */
+static int wc_PKCS7_KariGenerateKEK(WC_PKCS7_KARI* kari,
+                                    int keyWrapOID, int keyEncOID)
+{
+    int ret;
+    int kSz;
+    enum wc_HashType kdfType;
+    byte*  secret;
+    word32 secretSz;
+
+    if (kari == NULL || kari->recipKey == NULL ||
+        kari->senderKey == NULL || kari->senderKey->dp == NULL)
+        return BAD_FUNC_ARG;
+
+    /* get KEK size, allocate buff */
+    kSz = wc_PKCS7_GetOIDKeySize(keyWrapOID);
+    if (kSz < 0)
+        return kSz;
+
+    kari->kek = (byte*)XMALLOC(kSz, kari->heap, DYNAMIC_TYPE_PKCS7);
+    if (kari->kek == NULL)
+        return MEMORY_E;
+
+    kari->kekSz = (word32)kSz;
+
+    /* generate ECC-CMS-SharedInfo */
+    ret = wc_PKCS7_KariGenerateSharedInfo(kari, keyWrapOID);
+    if (ret != 0)
+        return ret;
+
+    /* generate shared secret */
+    secretSz = kari->senderKey->dp->size;
+    secret = (byte*)XMALLOC(secretSz, kari->heap, DYNAMIC_TYPE_PKCS7);
+    if (secret == NULL)
+        return MEMORY_E;
+
+    if (kari->direction == WC_PKCS7_ENCODE) {
+
+        ret = wc_ecc_shared_secret(kari->senderKey, kari->recipKey,
+                                   secret, &secretSz);
+
+    } else if (kari->direction == WC_PKCS7_DECODE) {
+
+        ret = wc_ecc_shared_secret(kari->recipKey, kari->senderKey,
+                                   secret, &secretSz);
+
+    } else {
+        /* bad direction */
+        XFREE(secret, kari->heap, DYNAMIC_TYPE_PKCS7);
+        return BAD_FUNC_ARG;
+    }
+
+    if (ret != 0) {
+        XFREE(secret, kari->heap, DYNAMIC_TYPE_PKCS7);
+        return ret;
+    }
+
+    /* run through KDF */
+    switch (keyEncOID) {
+
+    #ifndef NO_SHA
+        case dhSinglePass_stdDH_sha1kdf_scheme:
+            kdfType = WC_HASH_TYPE_SHA;
+            break;
+    #endif
+    #ifndef WOLFSSL_SHA224
+        case dhSinglePass_stdDH_sha224kdf_scheme:
+            kdfType = WC_HASH_TYPE_SHA224;
+            break;
+    #endif
+    #ifndef NO_SHA256
+        case dhSinglePass_stdDH_sha256kdf_scheme:
+            kdfType = WC_HASH_TYPE_SHA256;
+            break;
+    #endif
+    #ifdef WOLFSSL_SHA384
+        case dhSinglePass_stdDH_sha384kdf_scheme:
+            kdfType = WC_HASH_TYPE_SHA384;
+            break;
+    #endif
+    #ifdef WOLFSSL_SHA512
+        case dhSinglePass_stdDH_sha512kdf_scheme:
+            kdfType = WC_HASH_TYPE_SHA512;
+            break;
+    #endif
+        default:
+            WOLFSSL_MSG("Unsupported key agreement algorithm");
+            XFREE(secret, kari->heap, DYNAMIC_TYPE_PKCS7);
+            return BAD_FUNC_ARG;
+    };
+
+    ret = wc_X963_KDF(kdfType, secret, secretSz, kari->sharedInfo,
+                      kari->sharedInfoSz, kari->kek, kari->kekSz);
+    if (ret != 0) {
+        XFREE(secret, kari->heap, DYNAMIC_TYPE_PKCS7);
+        return ret;
+    }
+
+    XFREE(secret, kari->heap, DYNAMIC_TYPE_PKCS7);
+
+    return 0;
+}
+
+
+/* create ASN.1 formatted KeyAgreeRecipientInfo (kari) for use with ECDH,
+ * return sequence size or negative on error */
+static int wc_CreateKeyAgreeRecipientInfo(PKCS7* pkcs7, const byte* cert,
+                            word32 certSz, int keyAgreeAlgo, int blockKeySz,
+                            int keyWrapAlgo, int keyEncAlgo, WC_RNG* rng,
+                            byte* contentKeyPlain, byte* contentKeyEnc,
+                            int* keyEncSz, byte* out, word32 outSz)
+{
+    int ret = 0, idx = 0;
+    int keySz, direction = 0;
+
+    /* ASN.1 layout */
+    int totalSz = 0;
+    int kariSeqSz = 0;
+    byte kariSeq[MAX_SEQ_SZ];           /* IMPLICIT [1] */
+    int verSz = 0;
+    byte ver[MAX_VERSION_SZ];
+
+    int origIdOrKeySeqSz = 0;
+    byte origIdOrKeySeq[MAX_SEQ_SZ];    /* IMPLICIT [0] */
+    int origPubKeySeqSz = 0;
+    byte origPubKeySeq[MAX_SEQ_SZ];     /* IMPLICIT [1] */
+    int origAlgIdSz = 0;
+    byte origAlgId[MAX_ALGO_SZ];
+    int origPubKeyStrSz = 0;
+    byte origPubKeyStr[MAX_OCTET_STR_SZ];
+
+    /* optional user keying material */
+    int ukmOctetSz = 0;
+    byte ukmOctetStr[MAX_OCTET_STR_SZ];
+    int ukmExplicitSz = 0;
+    byte ukmExplicitSeq[MAX_SEQ_SZ];
+
+    int keyEncryptAlgoIdSz = 0;
+    byte keyEncryptAlgoId[MAX_ALGO_SZ];
+    int keyWrapAlgSz = 0;
+    byte keyWrapAlg[MAX_ALGO_SZ];
+
+    int recipEncKeysSeqSz = 0;
+    byte recipEncKeysSeq[MAX_SEQ_SZ];
+    int recipEncKeySeqSz = 0;
+    byte recipEncKeySeq[MAX_SEQ_SZ];
+    int recipKeyIdSeqSz = 0;
+    byte recipKeyIdSeq[MAX_SEQ_SZ];     /* IMPLICIT [0] */
+    int subjKeyIdOctetSz = 0;
+    byte subjKeyIdOctet[MAX_OCTET_STR_SZ];
+    int encryptedKeyOctetSz = 0;
+    byte encryptedKeyOctet[MAX_OCTET_STR_SZ];
+
+    WC_PKCS7_KARI* kari;
+
+    /* only supports ECDSA for now */
+    if (keyAgreeAlgo != ECDSAk)
+        return BAD_FUNC_ARG;
+
+    /* set direction based on keyWrapAlgo */
+    switch (keyWrapAlgo) {
+#ifndef NO_AES
+        case AES128_WRAP:
+        case AES192_WRAP:
+        case AES256_WRAP:
+            direction = AES_ENCRYPTION;
+            break;
+#endif
+        default:
+            WOLFSSL_MSG("Unsupported key wrap algorithm");
+            return BAD_KEYWRAP_ALG_E;
+    }
+
+    kari = wc_PKCS7_KariNew(pkcs7, WC_PKCS7_ENCODE);
+    if (kari == NULL)
+        return MEMORY_E;
+
+    /* set user keying material if available */
+    if ((pkcs7->ukmSz > 0) && (pkcs7->ukm != NULL)) {
+        kari->ukm = pkcs7->ukm;
+        kari->ukmSz = pkcs7->ukmSz;
+        kari->ukmOwner = 0;
+    }
+
+    /* parse recipient cert, get public key */
+    ret = wc_PKCS7_KariParseRecipCert(kari, cert, certSz, NULL, 0);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        return ret;
+    }
+
+    /* generate sender ephemeral ECC key */
+    ret = wc_PKCS7_KariGenerateEphemeralKey(kari, rng);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        return ret;
+    }
+
+    /* generate KEK (key encryption key) */
+    ret = wc_PKCS7_KariGenerateKEK(kari, keyWrapAlgo, keyEncAlgo);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        return ret;
+    }
+
+    /* encrypt CEK with KEK */
+    keySz = wc_PKCS7_KariKeyWrap(contentKeyPlain, blockKeySz, kari->kek,
+                        kari->kekSz, contentKeyEnc, *keyEncSz, keyWrapAlgo,
+                        direction);
+    if (keySz <= 0) {
+        wc_PKCS7_KariFree(kari);
+        return ret;
+    }
+    *keyEncSz = (word32)keySz;
+
+    /* Start of RecipientEncryptedKeys */
+
+    /* EncryptedKey */
+    encryptedKeyOctetSz = SetOctetString(*keyEncSz, encryptedKeyOctet);
+    totalSz += (encryptedKeyOctetSz + *keyEncSz);
+
+    /* SubjectKeyIdentifier */
+    subjKeyIdOctetSz = SetOctetString(KEYID_SIZE, subjKeyIdOctet);
+    totalSz += (subjKeyIdOctetSz + KEYID_SIZE);
+
+    /* RecipientKeyIdentifier IMPLICIT [0] */
+    recipKeyIdSeqSz = SetImplicit(ASN_SEQUENCE, 0, subjKeyIdOctetSz +
+                                  KEYID_SIZE, recipKeyIdSeq);
+    totalSz += recipKeyIdSeqSz;
+
+    /* RecipientEncryptedKey */
+    recipEncKeySeqSz = SetSequence(totalSz, recipEncKeySeq);
+    totalSz += recipEncKeySeqSz;
+
+    /* RecipientEncryptedKeys */
+    recipEncKeysSeqSz = SetSequence(totalSz, recipEncKeysSeq);
+    totalSz += recipEncKeysSeqSz;
+
+    /* Start of optional UserKeyingMaterial */
+
+    if (kari->ukmSz > 0) {
+        ukmOctetSz = SetOctetString(kari->ukmSz, ukmOctetStr);
+        totalSz += (ukmOctetSz + kari->ukmSz);
+
+        ukmExplicitSz = SetExplicit(1, ukmOctetSz + kari->ukmSz,
+                                    ukmExplicitSeq);
+        totalSz += ukmExplicitSz;
+    }
+
+    /* Start of KeyEncryptionAlgorithmIdentifier */
+
+    /* KeyWrapAlgorithm */
+    keyWrapAlgSz = SetAlgoID(keyWrapAlgo, keyWrapAlg, oidKeyWrapType, 0);
+    totalSz += keyWrapAlgSz;
+
+    /* KeyEncryptionAlgorithmIdentifier */
+    keyEncryptAlgoIdSz = SetAlgoID(keyEncAlgo, keyEncryptAlgoId,
+                                   oidCmsKeyAgreeType, keyWrapAlgSz);
+    totalSz += keyEncryptAlgoIdSz;
+
+    /* Start of OriginatorIdentifierOrKey */
+
+    /* recipient ECPoint, public key */
+    XMEMSET(origPubKeyStr, 0, sizeof(origPubKeyStr)); /* no unused bits */
+    origPubKeyStr[0] = ASN_BIT_STRING;
+    origPubKeyStrSz = SetLength(kari->senderKeyExportSz + 1,
+                                origPubKeyStr + 1) + 2;
+    totalSz += (origPubKeyStrSz + kari->senderKeyExportSz);
+
+    /* Originator AlgorithmIdentifier */
+    origAlgIdSz = SetAlgoID(ECDSAk, origAlgId, oidKeyType, 0);
+    totalSz += origAlgIdSz;
+
+    /* outer OriginatorPublicKey IMPLICIT [1] */
+    origPubKeySeqSz = SetImplicit(ASN_SEQUENCE, 1,
+                                  origAlgIdSz + origPubKeyStrSz +
+                                  kari->senderKeyExportSz, origPubKeySeq);
+    totalSz += origPubKeySeqSz;
+
+    /* outer OriginatorIdentiferOrKey IMPLICIT [0] */
+    origIdOrKeySeqSz = SetImplicit(ASN_SEQUENCE, 0,
+                                   origPubKeySeqSz + origAlgIdSz +
+                                   origPubKeyStrSz + kari->senderKeyExportSz,
+                                   origIdOrKeySeq);
+    totalSz += origIdOrKeySeqSz;
+
+    /* version, always 3 */
+    verSz = SetMyVersion(3, ver, 0);
+    totalSz += verSz;
+
+    /* outer IMPLICIT [1] kari */
+    kariSeqSz = SetImplicit(ASN_SEQUENCE, 1, totalSz, kariSeq);
+    totalSz += kariSeqSz;
+
+    if ((word32)totalSz > outSz) {
+        WOLFSSL_MSG("KeyAgreeRecipientInfo output buffer too small");
+        wc_PKCS7_KariFree(kari);
+
+        return BUFFER_E;
+    }
+
+    XMEMCPY(out + idx, kariSeq, kariSeqSz);
+    idx += kariSeqSz;
+    XMEMCPY(out + idx, ver, verSz);
+    idx += verSz;
+
+    XMEMCPY(out + idx, origIdOrKeySeq, origIdOrKeySeqSz);
+    idx += origIdOrKeySeqSz;
+    XMEMCPY(out + idx, origPubKeySeq, origPubKeySeqSz);
+    idx += origPubKeySeqSz;
+    XMEMCPY(out + idx, origAlgId, origAlgIdSz);
+    idx += origAlgIdSz;
+    XMEMCPY(out + idx, origPubKeyStr, origPubKeyStrSz);
+    idx += origPubKeyStrSz;
+    /* ephemeral public key */
+    XMEMCPY(out + idx, kari->senderKeyExport, kari->senderKeyExportSz);
+    idx += kari->senderKeyExportSz;
+
+    if (kari->ukmSz > 0) {
+        XMEMCPY(out + idx, ukmExplicitSeq, ukmExplicitSz);
+        idx += ukmExplicitSz;
+        XMEMCPY(out + idx, ukmOctetStr, ukmOctetSz);
+        idx += ukmOctetSz;
+        XMEMCPY(out + idx, kari->ukm, kari->ukmSz);
+        idx += kari->ukmSz;
+    }
+
+    XMEMCPY(out + idx, keyEncryptAlgoId, keyEncryptAlgoIdSz);
+    idx += keyEncryptAlgoIdSz;
+    XMEMCPY(out + idx, keyWrapAlg, keyWrapAlgSz);
+    idx += keyWrapAlgSz;
+
+    XMEMCPY(out + idx, recipEncKeysSeq, recipEncKeysSeqSz);
+    idx += recipEncKeysSeqSz;
+    XMEMCPY(out + idx, recipEncKeySeq, recipEncKeySeqSz);
+    idx += recipEncKeySeqSz;
+    XMEMCPY(out + idx, recipKeyIdSeq, recipKeyIdSeqSz);
+    idx += recipKeyIdSeqSz;
+    XMEMCPY(out + idx, subjKeyIdOctet, subjKeyIdOctetSz);
+    idx += subjKeyIdOctetSz;
+    /* subject key id */
+    XMEMCPY(out + idx, kari->decoded->extSubjKeyId, KEYID_SIZE);
+    idx += KEYID_SIZE;
+    XMEMCPY(out + idx, encryptedKeyOctet, encryptedKeyOctetSz);
+    idx += encryptedKeyOctetSz;
+    /* encrypted CEK */
+    XMEMCPY(out + idx, contentKeyEnc, *keyEncSz);
+    idx += *keyEncSz;
+
+    wc_PKCS7_KariFree(kari);
+
+    return idx;
+}
+
+#endif /* HAVE_ECC */
+
+
+/* create ASN.1 formatted RecipientInfo structure, returns sequence size */
+static int wc_CreateRecipientInfo(const byte* cert, word32 certSz,
+                                  int keyEncAlgo, int blockKeySz,
+                                  WC_RNG* rng, byte* contentKeyPlain,
+                                  byte* contentKeyEnc, int* keyEncSz,
+                                  byte* out, word32 outSz, void* heap)
+{
+    word32 idx = 0;
+    int ret = 0, totalSz = 0;
+    int verSz, issuerSz, snSz, keyEncAlgSz;
+    int issuerSeqSz, recipSeqSz, issuerSerialSeqSz;
+    int encKeyOctetStrSz;
+
+    byte ver[MAX_VERSION_SZ];
+    byte issuerSerialSeq[MAX_SEQ_SZ];
+    byte recipSeq[MAX_SEQ_SZ];
+    byte issuerSeq[MAX_SEQ_SZ];
+    byte encKeyOctetStr[MAX_OCTET_STR_SZ];
+
+#ifdef WOLFSSL_SMALL_STACK
+    byte *serial;
+    byte *keyAlgArray;
+
+    RsaKey* pubKey;
+    DecodedCert* decoded;
+
+    serial = (byte*)XMALLOC(MAX_SN_SZ, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    keyAlgArray = (byte*)XMALLOC(MAX_SN_SZ, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    decoded = (DecodedCert*)XMALLOC(sizeof(DecodedCert), NULL,
+                                                       DYNAMIC_TYPE_TMP_BUFFER);
+
+    if (decoded == NULL || serial == NULL || keyAlgArray == NULL) {
+        if (serial)      XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        if (keyAlgArray) XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        if (decoded)     XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        return MEMORY_E;
+    }
+
+#else
+    byte serial[MAX_SN_SZ];
+    byte keyAlgArray[MAX_ALGO_SZ];
+
+    RsaKey stack_pubKey;
+    RsaKey* pubKey = &stack_pubKey;
+    DecodedCert stack_decoded;
+    DecodedCert* decoded = &stack_decoded;
+#endif
+
+    InitDecodedCert(decoded, (byte*)cert, certSz, heap);
+    ret = ParseCert(decoded, CA_TYPE, NO_VERIFY, 0);
+    if (ret < 0) {
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    /* version */
+    verSz = SetMyVersion(0, ver, 0);
+
+    /* IssuerAndSerialNumber */
+    if (decoded->issuerRaw == NULL || decoded->issuerRawLen == 0) {
+        WOLFSSL_MSG("DecodedCert lacks raw issuer pointer and length");
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return -1;
+    }
+    issuerSz    = decoded->issuerRawLen;
+    issuerSeqSz = SetSequence(issuerSz, issuerSeq);
+
+    if (decoded->serialSz == 0) {
+        WOLFSSL_MSG("DecodedCert missing serial number");
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return -1;
+    }
+    snSz = SetSerialNumber(decoded->serial, decoded->serialSz, serial);
+
+    issuerSerialSeqSz = SetSequence(issuerSeqSz + issuerSz + snSz,
+                                    issuerSerialSeq);
+
+    /* KeyEncryptionAlgorithmIdentifier, only support RSA now */
+    if (keyEncAlgo != RSAk) {
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ALGO_ID_E;
+    }
+
+    keyEncAlgSz = SetAlgoID(keyEncAlgo, keyAlgArray, oidKeyType, 0);
+    if (keyEncAlgSz == 0) {
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return BAD_FUNC_ARG;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    pubKey = (RsaKey*)XMALLOC(sizeof(RsaKey), NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (pubKey == NULL) {
+        FreeDecodedCert(decoded);
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        return MEMORY_E;
+    }
+#endif
+
+    /* EncryptedKey */
+    ret = wc_InitRsaKey(pubKey, 0);
+    if (ret != 0) {
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(pubKey,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    if (wc_RsaPublicKeyDecode(decoded->publicKey, &idx, pubKey,
+                           decoded->pubKeySize) < 0) {
+        WOLFSSL_MSG("ASN RSA key decode error");
+        wc_FreeRsaKey(pubKey);
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(pubKey,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return PUBLIC_KEY_E;
+    }
+
+    *keyEncSz = wc_RsaPublicEncrypt(contentKeyPlain, blockKeySz, contentKeyEnc,
+                                 MAX_ENCRYPTED_KEY_SZ, pubKey, rng);
+    wc_FreeRsaKey(pubKey);
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(pubKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    if (*keyEncSz < 0) {
+        WOLFSSL_MSG("RSA Public Encrypt failed");
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return *keyEncSz;
+    }
+
+    encKeyOctetStrSz = SetOctetString(*keyEncSz, encKeyOctetStr);
+
+    /* RecipientInfo */
+    recipSeqSz = SetSequence(verSz + issuerSerialSeqSz + issuerSeqSz +
+                             issuerSz + snSz + keyEncAlgSz + encKeyOctetStrSz +
+                             *keyEncSz, recipSeq);
+
+    if (recipSeqSz + verSz + issuerSerialSeqSz + issuerSeqSz + snSz +
+        keyEncAlgSz + encKeyOctetStrSz + *keyEncSz > (int)outSz) {
+        WOLFSSL_MSG("RecipientInfo output buffer too small");
+        FreeDecodedCert(decoded);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return BUFFER_E;
+    }
+
+    XMEMCPY(out + totalSz, recipSeq, recipSeqSz);
+    totalSz += recipSeqSz;
+    XMEMCPY(out + totalSz, ver, verSz);
+    totalSz += verSz;
+    XMEMCPY(out + totalSz, issuerSerialSeq, issuerSerialSeqSz);
+    totalSz += issuerSerialSeqSz;
+    XMEMCPY(out + totalSz, issuerSeq, issuerSeqSz);
+    totalSz += issuerSeqSz;
+    XMEMCPY(out + totalSz, decoded->issuerRaw, issuerSz);
+    totalSz += issuerSz;
+    XMEMCPY(out + totalSz, serial, snSz);
+    totalSz += snSz;
+    XMEMCPY(out + totalSz, keyAlgArray, keyEncAlgSz);
+    totalSz += keyEncAlgSz;
+    XMEMCPY(out + totalSz, encKeyOctetStr, encKeyOctetStrSz);
+    totalSz += encKeyOctetStrSz;
+    XMEMCPY(out + totalSz, contentKeyEnc, *keyEncSz);
+    totalSz += *keyEncSz;
+
+    FreeDecodedCert(decoded);
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    XFREE(keyAlgArray, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    XFREE(decoded,     NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return totalSz;
+}
+
+
+/* encrypt content using encryptOID algo */
+static int wc_PKCS7_EncryptContent(int encryptOID, byte* key, int keySz,
+                                   byte* iv, int ivSz, byte* in, int inSz,
+                                   byte* out)
+{
+    int ret;
+#ifndef NO_AES
+    Aes  aes;
+#endif
+#ifndef NO_DES3
+    Des  des;
+    Des3 des3;
+#endif
+
+    if (key == NULL || iv == NULL || in == NULL || out == NULL)
+        return BAD_FUNC_ARG;
+
+    switch (encryptOID) {
+#ifndef NO_AES
+        case AES128CBCb:
+        case AES192CBCb:
+        case AES256CBCb:
+            if ( (encryptOID == AES128CBCb && keySz != 16 ) ||
+                 (encryptOID == AES192CBCb && keySz != 24 ) ||
+                 (encryptOID == AES256CBCb && keySz != 32 ) ||
+                 (ivSz  != AES_BLOCK_SIZE) )
+                return BAD_FUNC_ARG;
+
+            ret = wc_AesSetKey(&aes, key, keySz, iv, AES_ENCRYPTION);
+            if (ret == 0)
+                ret = wc_AesCbcEncrypt(&aes, out, in, inSz);
+
+            break;
+#endif
+#ifndef NO_DES3
+        case DESb:
+            if (keySz != DES_KEYLEN || ivSz != DES_BLOCK_SIZE)
+                return BAD_FUNC_ARG;
+
+            ret = wc_Des_SetKey(&des, key, iv, DES_ENCRYPTION);
+            if (ret == 0)
+                ret = wc_Des_CbcEncrypt(&des, out, in, inSz);
+
+            break;
+
+        case DES3b:
+            if (keySz != DES3_KEYLEN || ivSz != DES_BLOCK_SIZE)
+                return BAD_FUNC_ARG;
+
+            ret = wc_Des3_SetKey(&des3, key, iv, DES_ENCRYPTION);
+            if (ret == 0)
+                ret = wc_Des3_CbcEncrypt(&des3, out, in, inSz);
+
+            break;
+#endif
+        default:
+            WOLFSSL_MSG("Unsupported content cipher type");
+            return ALGO_ID_E;
+    };
+
+    return ret;
+}
+
+
+/* decrypt content using encryptOID algo */
+static int wc_PKCS7_DecryptContent(int encryptOID, byte* key, int keySz,
+                                   byte* iv, int ivSz, byte* in, int inSz,
+                                   byte* out)
+{
+    int ret;
+#ifndef NO_AES
+    Aes  aes;
+#endif
+#ifndef NO_DES3
+    Des  des;
+    Des3 des3;
+#endif
+
+    if (key == NULL || iv == NULL || in == NULL || out == NULL)
+        return BAD_FUNC_ARG;
+
+    switch (encryptOID) {
+#ifndef NO_AES
+        case AES128CBCb:
+        case AES192CBCb:
+        case AES256CBCb:
+            if ( (encryptOID == AES128CBCb && keySz != 16 ) ||
+                 (encryptOID == AES192CBCb && keySz != 24 ) ||
+                 (encryptOID == AES256CBCb && keySz != 32 ) ||
+                 (ivSz  != AES_BLOCK_SIZE) )
+                return BAD_FUNC_ARG;
+
+            ret = wc_AesSetKey(&aes, key, keySz, iv, AES_DECRYPTION);
+            if (ret == 0)
+                ret = wc_AesCbcDecrypt(&aes, out, in, inSz);
+
+            break;
+#endif
+#ifndef NO_DES3
+        case DESb:
+            if (keySz != DES_KEYLEN || ivSz != DES_BLOCK_SIZE)
+                return BAD_FUNC_ARG;
+
+            ret = wc_Des_SetKey(&des, key, iv, DES_DECRYPTION);
+            if (ret == 0)
+                ret = wc_Des_CbcDecrypt(&des, out, in, inSz);
+
+            break;
+        case DES3b:
+            if (keySz != DES3_KEYLEN || ivSz != DES_BLOCK_SIZE)
+                return BAD_FUNC_ARG;
+
+            ret = wc_Des3_SetKey(&des3, key, iv, DES_DECRYPTION);
+            if (ret == 0)
+                ret = wc_Des3_CbcDecrypt(&des3, out, in, inSz);
+
+            break;
+#endif
+        default:
+            WOLFSSL_MSG("Unsupported content cipher type");
+            return ALGO_ID_E;
+    };
+
+    return ret;
+}
+
+
+/* generate random IV, place in iv, return 0 on success negative on error */
+static int wc_PKCS7_GenerateIV(PKCS7* pkcs7, WC_RNG* rng, byte* iv, word32 ivSz)
+{
+    int ret;
+    WC_RNG* rnd = NULL;
+
+    if (iv == NULL || ivSz == 0)
+        return BAD_FUNC_ARG;
+
+    /* input RNG is optional, init local one if input rng is NULL */
+    if (rng == NULL) {
+        rnd = (WC_RNG*)XMALLOC(sizeof(WC_RNG), pkcs7->heap, DYNAMIC_TYPE_RNG);
+        if (rnd == NULL)
+            return MEMORY_E;
+
+        ret = wc_InitRng_ex(rnd, pkcs7->heap, INVALID_DEVID);
+        if (ret != 0) {
+            XFREE(rnd, pkcs7->heap, DYNAMIC_TYPE_RNG);
+            return ret;
+        }
+
+    } else {
+        rnd = rng;
+    }
+
+    ret = wc_RNG_GenerateBlock(rnd, iv, ivSz);
+
+    if (rng == NULL) {
+        wc_FreeRng(rnd);
+        XFREE(rnd, pkcs7->heap, DYNAMIC_TYPE_RNG);
+    }
+
+    return ret;
+}
+
+
+/* return size of padded data, padded to blockSz chunks, or negative on error */
+static int wc_PKCS7_GetPadSize(word32 inputSz, word32 blockSz)
+{
+    int padSz;
+
+    if (blockSz == 0)
+        return BAD_FUNC_ARG;
+
+    padSz = blockSz - (inputSz % blockSz);
+
+    return padSz;
+}
+
+
+/* pad input data to blockSz chunk, place in outSz. out must be big enough
+ * for input + pad bytes. See wc_PKCS7_GetPadLength() helper. */
+static int wc_PKCS7_PadData(byte* in, word32 inSz, byte* out, word32 outSz,
+                            word32 blockSz)
+{
+    int i, padSz;
+
+    if (in == NULL  || inSz == 0 ||
+        out == NULL || outSz == 0)
+        return BAD_FUNC_ARG;
+
+    padSz = blockSz - (inSz % blockSz);
+
+    if (outSz < (inSz + padSz))
+        return BAD_FUNC_ARG;
+
+    XMEMCPY(out, in, inSz);
+
+    for (i = 0; i < padSz; i++) {
+        out[inSz + i] = (byte)padSz;
+    }
+
+    return inSz + padSz;
+}
+
+
+/* build PKCS#7 envelopedData content type, return enveloped size */
+int wc_PKCS7_EncodeEnvelopedData(PKCS7* pkcs7, byte* output, word32 outputSz)
+{
+    int ret, idx = 0;
+    int totalSz, padSz, encryptedOutSz;
+
+    int contentInfoSeqSz, outerContentTypeSz, outerContentSz;
+    byte contentInfoSeq[MAX_SEQ_SZ];
+    byte outerContentType[MAX_ALGO_SZ];
+    byte outerContent[MAX_SEQ_SZ];
+
+    int envDataSeqSz, verSz;
+    byte envDataSeq[MAX_SEQ_SZ];
+    byte ver[MAX_VERSION_SZ];
+
+    WC_RNG rng;
+    int contentKeyEncSz, blockSz, blockKeySz;
+    byte contentKeyPlain[MAX_CONTENT_KEY_LEN];
+#ifdef WOLFSSL_SMALL_STACK
+    byte* contentKeyEnc;
+#else
+    byte contentKeyEnc[MAX_ENCRYPTED_KEY_SZ];
+#endif
+    byte* plain;
+    byte* encryptedContent;
+
+    int recipSz, recipSetSz;
+#ifdef WOLFSSL_SMALL_STACK
+    byte* recip;
+#else
+    byte recip[MAX_RECIP_SZ];
+#endif
+    byte recipSet[MAX_SET_SZ];
+
+    int encContentOctetSz, encContentSeqSz, contentTypeSz;
+    int contentEncAlgoSz, ivOctetStringSz;
+    byte encContentSeq[MAX_SEQ_SZ];
+    byte contentType[MAX_ALGO_SZ];
+    byte contentEncAlgo[MAX_ALGO_SZ];
+    byte tmpIv[MAX_CONTENT_IV_SIZE];
+    byte ivOctetString[MAX_OCTET_STR_SZ];
+    byte encContentOctet[MAX_OCTET_STR_SZ];
+
+    if (pkcs7 == NULL || pkcs7->content == NULL || pkcs7->contentSz == 0 ||
+        pkcs7->encryptOID == 0 || pkcs7->singleCert == NULL ||
+        pkcs7->publicKeyOID == 0)
+        return BAD_FUNC_ARG;
+
+    if (output == NULL || outputSz == 0)
+        return BAD_FUNC_ARG;
+
+    blockKeySz = wc_PKCS7_GetOIDKeySize(pkcs7->encryptOID);
+    if (blockKeySz < 0)
+        return blockKeySz;
+
+    blockSz = wc_PKCS7_GetOIDBlockSize(pkcs7->encryptOID);
+    if (blockSz < 0)
+        return blockSz;
+
+    /* outer content type */
+    outerContentTypeSz = wc_SetContentType(ENVELOPED_DATA, outerContentType);
+
+    /* version, defined as 0 in RFC 2315 */
+    if (pkcs7->publicKeyOID == ECDSAk) {
+        verSz = SetMyVersion(2, ver, 0);
+    } else {
+        verSz = SetMyVersion(0, ver, 0);
+    }
+
+    /* generate random content encryption key */
+    ret = wc_InitRng_ex(&rng, pkcs7->heap, INVALID_DEVID);
+    if (ret != 0)
+        return ret;
+
+    ret = wc_RNG_GenerateBlock(&rng, contentKeyPlain, blockKeySz);
+    if (ret != 0) {
+        wc_FreeRng(&rng);
+        return ret;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    recip         = (byte*)XMALLOC(MAX_RECIP_SZ, NULL, DYNAMIC_TYPE_PKCS7);
+    contentKeyEnc = (byte*)XMALLOC(MAX_ENCRYPTED_KEY_SZ, NULL,
+                                                       DYNAMIC_TYPE_PKCS7);
+    if (contentKeyEnc == NULL || recip == NULL) {
+        if (recip)         XFREE(recip,         NULL, DYNAMIC_TYPE_PKCS7);
+        if (contentKeyEnc) XFREE(contentKeyEnc, NULL, DYNAMIC_TYPE_PKCS7);
+        wc_FreeRng(&rng);
+        return MEMORY_E;
+    }
+#endif
+    contentKeyEncSz = MAX_ENCRYPTED_KEY_SZ;
+
+    /* build RecipientInfo, only handle 1 for now */
+    switch (pkcs7->publicKeyOID) {
+
+        case RSAk:
+            recipSz = wc_CreateRecipientInfo(pkcs7->singleCert,
+                                    pkcs7->singleCertSz,
+                                    pkcs7->publicKeyOID,
+                                    blockKeySz, &rng, contentKeyPlain,
+                                    contentKeyEnc, &contentKeyEncSz, recip,
+                                    MAX_RECIP_SZ, pkcs7->heap);
+            break;
+
+#ifdef HAVE_ECC
+        case ECDSAk:
+            recipSz = wc_CreateKeyAgreeRecipientInfo(pkcs7, pkcs7->singleCert,
+                                    pkcs7->singleCertSz,
+                                    pkcs7->publicKeyOID,
+                                    blockKeySz, pkcs7->keyWrapOID,
+                                    pkcs7->keyAgreeOID, &rng,
+                                    contentKeyPlain, contentKeyEnc,
+                                    &contentKeyEncSz, recip, MAX_RECIP_SZ);
+            break;
+#endif
+
+        default:
+            WOLFSSL_MSG("Unsupported RecipientInfo public key type");
+            return BAD_FUNC_ARG;
+    };
+
+    ForceZero(contentKeyEnc, MAX_ENCRYPTED_KEY_SZ);
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(contentKeyEnc, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+
+    if (recipSz < 0) {
+        WOLFSSL_MSG("Failed to create RecipientInfo");
+        wc_FreeRng(&rng);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(recip, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return recipSz;
+    }
+    recipSetSz = SetSet(recipSz, recipSet);
+
+    /* generate IV for block cipher */
+    ret = wc_PKCS7_GenerateIV(pkcs7, &rng, tmpIv, blockSz);
+    wc_FreeRng(&rng);
+    if (ret != 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(recip, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    /* EncryptedContentInfo */
+    contentTypeSz = wc_SetContentType(pkcs7->contentOID, contentType);
+    if (contentTypeSz == 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(recip, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return BAD_FUNC_ARG;
+    }
+
+    /* allocate encrypted content buffer and PKCS#7 padding */
+    padSz = wc_PKCS7_GetPadSize(pkcs7->contentSz, blockSz);
+    if (padSz < 0)
+        return padSz;
+
+    encryptedOutSz = pkcs7->contentSz + padSz;
+
+    plain = (byte*)XMALLOC(encryptedOutSz, pkcs7->heap,
+                           DYNAMIC_TYPE_PKCS7);
+    if (plain == NULL)
+        return MEMORY_E;
+
+    ret = wc_PKCS7_PadData(pkcs7->content, pkcs7->contentSz, plain,
+                           encryptedOutSz, blockSz);
+    if (ret < 0) {
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return ret;
+    }
+
+    encryptedContent = (byte*)XMALLOC(encryptedOutSz, pkcs7->heap,
+                                      DYNAMIC_TYPE_PKCS7);
+    if (encryptedContent == NULL) {
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(recip, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return MEMORY_E;
+    }
+
+    /* put together IV OCTET STRING */
+    ivOctetStringSz = SetOctetString(blockSz, ivOctetString);
+
+    /* build up our ContentEncryptionAlgorithmIdentifier sequence,
+     * adding (ivOctetStringSz + blockSz) for IV OCTET STRING */
+    contentEncAlgoSz = SetAlgoID(pkcs7->encryptOID, contentEncAlgo,
+                                 oidBlkType, ivOctetStringSz + blockSz);
+
+    if (contentEncAlgoSz == 0) {
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(recip, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return BAD_FUNC_ARG;
+    }
+
+    /* encrypt content */
+    ret = wc_PKCS7_EncryptContent(pkcs7->encryptOID, contentKeyPlain,
+            blockKeySz, tmpIv, blockSz, plain, encryptedOutSz,
+            encryptedContent);
+
+    if (ret != 0) {
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(recip, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ret;
+    }
+
+    encContentOctetSz = SetImplicit(ASN_OCTET_STRING, 0, encryptedOutSz,
+                                    encContentOctet);
+
+    encContentSeqSz = SetSequence(contentTypeSz + contentEncAlgoSz +
+                                  ivOctetStringSz + blockSz +
+                                  encContentOctetSz + encryptedOutSz,
+                                  encContentSeq);
+
+    /* keep track of sizes for outer wrapper layering */
+    totalSz = verSz + recipSetSz + recipSz + encContentSeqSz + contentTypeSz +
+              contentEncAlgoSz + ivOctetStringSz + blockSz +
+              encContentOctetSz + encryptedOutSz;
+
+    /* EnvelopedData */
+    envDataSeqSz = SetSequence(totalSz, envDataSeq);
+    totalSz += envDataSeqSz;
+
+    /* outer content */
+    outerContentSz = SetExplicit(0, totalSz, outerContent);
+    totalSz += outerContentTypeSz;
+    totalSz += outerContentSz;
+
+    /* ContentInfo */
+    contentInfoSeqSz = SetSequence(totalSz, contentInfoSeq);
+    totalSz += contentInfoSeqSz;
+
+    if (totalSz > (int)outputSz) {
+        WOLFSSL_MSG("Pkcs7_encrypt output buffer too small");
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_TMP_BUFFER);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(recip, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return BUFFER_E;
+    }
+
+    XMEMCPY(output + idx, contentInfoSeq, contentInfoSeqSz);
+    idx += contentInfoSeqSz;
+    XMEMCPY(output + idx, outerContentType, outerContentTypeSz);
+    idx += outerContentTypeSz;
+    XMEMCPY(output + idx, outerContent, outerContentSz);
+    idx += outerContentSz;
+    XMEMCPY(output + idx, envDataSeq, envDataSeqSz);
+    idx += envDataSeqSz;
+    XMEMCPY(output + idx, ver, verSz);
+    idx += verSz;
+    XMEMCPY(output + idx, recipSet, recipSetSz);
+    idx += recipSetSz;
+    XMEMCPY(output + idx, recip, recipSz);
+    idx += recipSz;
+    XMEMCPY(output + idx, encContentSeq, encContentSeqSz);
+    idx += encContentSeqSz;
+    XMEMCPY(output + idx, contentType, contentTypeSz);
+    idx += contentTypeSz;
+    XMEMCPY(output + idx, contentEncAlgo, contentEncAlgoSz);
+    idx += contentEncAlgoSz;
+    XMEMCPY(output + idx, ivOctetString, ivOctetStringSz);
+    idx += ivOctetStringSz;
+    XMEMCPY(output + idx, tmpIv, blockSz);
+    idx += blockSz;
+    XMEMCPY(output + idx, encContentOctet, encContentOctetSz);
+    idx += encContentOctetSz;
+    XMEMCPY(output + idx, encryptedContent, encryptedOutSz);
+    idx += encryptedOutSz;
+
+    ForceZero(contentKeyPlain, MAX_CONTENT_KEY_LEN);
+
+    XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+    XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(recip, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return idx;
+}
+
+
+/* decode KeyTransRecipientInfo (ktri), return 0 on success, <0 on error */
+static int wc_PKCS7_DecodeKtri(PKCS7* pkcs7, byte* pkiMsg, word32 pkiMsgSz,
+                               word32* idx, byte* decryptedKey,
+                               word32* decryptedKeySz, int* recipFound)
+{
+    int length, encryptedKeySz, ret;
+    int keySz;
+    word32 encOID;
+    word32 keyIdx;
+    byte   issuerHash[SHA_DIGEST_SIZE];
+    byte*  outKey = NULL;
+
+#ifdef WC_RSA_BLINDING
+    WC_RNG rng;
+#endif
+
+#ifdef WOLFSSL_SMALL_STACK
+    mp_int* serialNum;
+    byte* encryptedKey;
+    RsaKey* privKey;
+#else
+    mp_int stack_serialNum;
+    mp_int* serialNum = &stack_serialNum;
+    byte encryptedKey[MAX_ENCRYPTED_KEY_SZ];
+
+    RsaKey stack_privKey;
+    RsaKey* privKey = &stack_privKey;
+#endif
+
+    /* remove IssuerAndSerialNumber */
+    if (GetSequence(pkiMsg, idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (GetNameHash(pkiMsg, idx, issuerHash, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* if we found correct recipient, issuer hashes will match */
+    if (XMEMCMP(issuerHash, pkcs7->issuerHash, SHA_DIGEST_SIZE) == 0) {
+        *recipFound = 1;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    serialNum = (mp_int*)XMALLOC(sizeof(mp_int), NULL,
+                                                   DYNAMIC_TYPE_TMP_BUFFER);
+    if (serialNum == NULL)
+        return MEMORY_E;
+#endif
+
+    if (GetInt(serialNum, pkiMsg, idx, pkiMsgSz) < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serialNum,    NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    mp_clear(serialNum);
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(serialNum, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    if (GetAlgoId(pkiMsg, idx, &encOID, oidKeyType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* key encryption algorithm must be RSA for now */
+    if (encOID != RSAk)
+        return ALGO_ID_E;
+
+    /* read encryptedKey */
+#ifdef WOLFSSL_SMALL_STACK
+    encryptedKey = (byte*)XMALLOC(MAX_ENCRYPTED_KEY_SZ, NULL,
+                                  DYNAMIC_TYPE_TMP_BUFFER);
+    if (encryptedKey == NULL)
+        return MEMORY_E;
+#endif
+
+    if (pkiMsg[(*idx)++] != ASN_OCTET_STRING) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(encryptedKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    if (GetLength(pkiMsg, idx, &encryptedKeySz, pkiMsgSz) < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(encryptedKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    if (*recipFound == 1)
+        XMEMCPY(encryptedKey, &pkiMsg[*idx], encryptedKeySz);
+    *idx += encryptedKeySz;
+
+    /* load private key */
+#ifdef WOLFSSL_SMALL_STACK
+    privKey = (RsaKey*)XMALLOC(sizeof(RsaKey), NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    if (privKey == NULL) {
+        XFREE(encryptedKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        return MEMORY_E;
+    }
+#endif
+
+    ret = wc_InitRsaKey(privKey, 0);
+    if (ret != 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(encryptedKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(privKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    keyIdx = 0;
+    ret = wc_RsaPrivateKeyDecode(pkcs7->privateKey, &keyIdx, privKey,
+                                 pkcs7->privateKeySz);
+    if (ret != 0) {
+        WOLFSSL_MSG("Failed to decode RSA private key");
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(encryptedKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(privKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    /* decrypt encryptedKey */
+    #ifdef WC_RSA_BLINDING
+    ret = wc_InitRng_ex(&rng, pkcs7->heap, INVALID_DEVID);
+    if (ret == 0) {
+        ret = wc_RsaSetRNG(privKey, &rng);
+    }
+    #endif
+    if (ret == 0) {
+        keySz = wc_RsaPrivateDecryptInline(encryptedKey, encryptedKeySz,
+                                           &outKey, privKey);
+        #ifdef WC_RSA_BLINDING
+            wc_FreeRng(&rng);
+        #endif
+    } else {
+        keySz = ret;
+    }
+    wc_FreeRsaKey(privKey);
+
+    if (keySz <= 0 || outKey == NULL) {
+        ForceZero(encryptedKey, MAX_ENCRYPTED_KEY_SZ);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(encryptedKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(privKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return keySz;
+    } else {
+        *decryptedKeySz = keySz;
+        XMEMCPY(decryptedKey, outKey, keySz);
+        ForceZero(encryptedKey, MAX_ENCRYPTED_KEY_SZ);
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(encryptedKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    XFREE(privKey, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return 0;
+}
+
+
+#ifdef HAVE_ECC
+
+/* remove ASN.1 OriginatorIdentifierOrKey, return 0 on success, <0 on error */
+static int wc_PKCS7_KariGetOriginatorIdentifierOrKey(WC_PKCS7_KARI* kari,
+                        byte* pkiMsg, word32 pkiMsgSz, word32* idx)
+{
+    int ret, length;
+    word32 keyOID;
+
+    if (kari == NULL || pkiMsg == NULL || idx == NULL)
+        return BAD_FUNC_ARG;
+
+    /* remove OriginatorIdentifierOrKey */
+    if (pkiMsg[*idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0)) {
+        (*idx)++;
+        if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+    } else {
+        return ASN_PARSE_E;
+    }
+
+    /* remove OriginatorPublicKey */
+    if (pkiMsg[*idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 1)) {
+        (*idx)++;
+        if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+    } else {
+        return ASN_PARSE_E;
+    }
+
+    /* remove AlgorithmIdentifier */
+    if (GetAlgoId(pkiMsg, idx, &keyOID, oidKeyType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (keyOID != ECDSAk)
+        return ASN_PARSE_E;
+
+    /* remove ECPoint BIT STRING */
+    if ((pkiMsgSz > (*idx + 1)) && (pkiMsg[(*idx)++] != ASN_BIT_STRING))
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if ((pkiMsgSz < (*idx + 1)) || (pkiMsg[(*idx)++] != 0x00))
+        return ASN_EXPECT_0_E;
+
+    /* get sender ephemeral public ECDSA key */
+    ret = wc_ecc_init_ex(kari->senderKey, kari->heap, INVALID_DEVID);
+    if (ret != 0)
+        return ret;
+
+    /* length-1 for unused bits counter */
+    ret = wc_ecc_import_x963(pkiMsg + (*idx), length - 1, kari->senderKey);
+    if (ret != 0)
+        return ret;
+
+    (*idx) += length - 1;
+
+    return 0;
+}
+
+
+/* remove optional UserKeyingMaterial if available, return 0 on success,
+ * < 0 on error */
+static int wc_PKCS7_KariGetUserKeyingMaterial(WC_PKCS7_KARI* kari,
+                        byte* pkiMsg, word32 pkiMsgSz, word32* idx)
+{
+    int length;
+    word32 savedIdx;
+
+    if (kari == NULL || pkiMsg == NULL || idx == NULL)
+        return BAD_FUNC_ARG;
+
+    savedIdx = *idx;
+
+    /* starts with EXPLICIT [1] */
+    if (pkiMsg[(*idx)++] != (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 1)) {
+        *idx = savedIdx;
+        return 0;
+    }
+
+    if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0) {
+        *idx = savedIdx;
+        return 0;
+    }
+
+    /* get OCTET STRING */
+    if ( (pkiMsgSz > ((*idx) + 1)) &&
+         (pkiMsg[(*idx)++] != ASN_OCTET_STRING) ) {
+        *idx = savedIdx;
+        return 0;
+    }
+
+    if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0) {
+        *idx = savedIdx;
+        return 0;
+    }
+
+    kari->ukm = NULL;
+    if (length > 0) {
+        kari->ukm = (byte*)XMALLOC(length, kari->heap, DYNAMIC_TYPE_PKCS7);
+        if (kari->ukm == NULL)
+            return MEMORY_E;
+
+        XMEMCPY(kari->ukm, pkiMsg + (*idx), length);
+        kari->ukmOwner = 1;
+    }
+
+    (*idx) += length;
+    kari->ukmSz = length;
+
+    return 0;
+}
+
+
+/* remove ASN.1 KeyEncryptionAlgorithmIdentifier, return 0 on success,
+ * < 0 on error */
+static int wc_PKCS7_KariGetKeyEncryptionAlgorithmId(WC_PKCS7_KARI* kari,
+                        byte* pkiMsg, word32 pkiMsgSz, word32* idx,
+                        word32* keyAgreeOID, word32* keyWrapOID)
+{
+    if (kari == NULL || pkiMsg == NULL || idx == NULL ||
+        keyAgreeOID == NULL || keyWrapOID == NULL)
+        return BAD_FUNC_ARG;
+
+    /* remove KeyEncryptionAlgorithmIdentifier */
+    if (GetAlgoId(pkiMsg, idx, keyAgreeOID, oidCmsKeyAgreeType,
+                  pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* remove KeyWrapAlgorithm, stored in parameter of KeyEncAlgoId */
+    if (GetAlgoId(pkiMsg, idx, keyWrapOID, oidKeyWrapType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    return 0;
+}
+
+
+/* remove ASN.1 SubjectKeyIdentifier, return 0 on success, < 0 on error
+ * if subject key ID matches, recipFound is set to 1 */
+static int wc_PKCS7_KariGetSubjectKeyIdentifier(WC_PKCS7_KARI* kari,
+                        byte* pkiMsg, word32 pkiMsgSz, word32* idx,
+                        int* recipFound)
+{
+    int length;
+    byte subjKeyId[KEYID_SIZE];
+
+    if (kari == NULL || pkiMsg == NULL || idx == NULL || recipFound == NULL)
+        return BAD_FUNC_ARG;
+
+    /* remove RecipientKeyIdentifier IMPLICIT [0] */
+    if ( (pkiMsgSz > (*idx + 1)) &&
+         (pkiMsg[(*idx)++] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0)) ) {
+
+        if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+    } else {
+        return ASN_PARSE_E;
+    }
+
+    /* remove SubjectKeyIdentifier */
+    if ( (pkiMsgSz > (*idx + 1)) &&
+         (pkiMsg[(*idx)++] != ASN_OCTET_STRING) )
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (length != KEYID_SIZE)
+        return ASN_PARSE_E;
+
+    XMEMCPY(subjKeyId, pkiMsg + (*idx), KEYID_SIZE);
+    (*idx) += length;
+
+    /* subject key id should match if recipient found */
+    if (XMEMCMP(subjKeyId, kari->decoded->extSubjKeyId, KEYID_SIZE) == 0) {
+        *recipFound = 1;
+    }
+
+    return 0;
+}
+
+
+/* remove ASN.1 IssuerAndSerialNumber, return 0 on success, < 0 on error
+ * if issuer and serial number match, recipFound is set to 1 */
+static int wc_PKCS7_KariGetIssuerAndSerialNumber(WC_PKCS7_KARI* kari,
+                        byte* pkiMsg, word32 pkiMsgSz, word32* idx,
+                        int* recipFound)
+{
+    int length, ret;
+    byte issuerHash[KEYID_SIZE];
+#ifdef WOLFSSL_SMALL_STACK
+    mp_int* serial;
+    mp_int* recipSerial;
+#else
+    mp_int  stack_serial;
+    mp_int* serial = &stack_serial;
+
+    mp_int  stack_recipSerial;
+    mp_int* recipSerial = &stack_recipSerial;
+#endif
+
+    /* remove IssuerAndSerialNumber */
+    if (GetSequence(pkiMsg, idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (GetNameHash(pkiMsg, idx, issuerHash, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* if we found correct recipient, issuer hashes will match */
+    if (XMEMCMP(issuerHash, kari->decoded->issuerHash, KEYID_SIZE) == 0) {
+        *recipFound = 1;
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    serial = (mp_int*)XMALLOC(sizeof(mp_int), NULL,
+                              DYNAMIC_TYPE_TMP_BUFFER);
+    if (serial == NULL)
+        return MEMORY_E;
+
+    recipSerial = (mp_int*)XMALLOC(sizeof(mp_int), NULL,
+                                   DYNAMIC_TYPE_TMP_BUFFER);
+    if (recipSerial == NULL) {
+        XFREE(serial, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        return MEMORY_E;
+    }
+#endif
+
+    if (GetInt(serial, pkiMsg, idx, pkiMsgSz) < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(recipSerial, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    ret = mp_read_unsigned_bin(recipSerial, kari->decoded->serial,
+                             kari->decoded->serialSz);
+    if (ret != MP_OKAY) {
+        mp_clear(serial);
+        WOLFSSL_MSG("Failed to parse CMS recipient serial number");
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(recipSerial, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return ret;
+    }
+
+    if (mp_cmp(recipSerial, serial) != MP_EQ) {
+        mp_clear(serial);
+        mp_clear(recipSerial);
+        WOLFSSL_MSG("CMS serial number does not match recipient");
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+        XFREE(recipSerial, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+        return PKCS7_RECIP_E;
+    }
+
+    mp_clear(serial);
+    mp_clear(recipSerial);
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(serial,      NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    XFREE(recipSerial, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    return 0;
+}
+
+
+/* remove ASN.1 RecipientEncryptedKeys, return 0 on success, < 0 on error */
+static int wc_PKCS7_KariGetRecipientEncryptedKeys(WC_PKCS7_KARI* kari,
+                        byte* pkiMsg, word32 pkiMsgSz, word32* idx,
+                        int* recipFound, byte* encryptedKey,
+                        int* encryptedKeySz)
+{
+    int length;
+    int ret = 0;
+
+    if (kari == NULL || pkiMsg == NULL || idx == NULL ||
+        recipFound == NULL || encryptedKey == NULL)
+        return BAD_FUNC_ARG;
+
+    /* remove RecipientEncryptedKeys */
+    if (GetSequence(pkiMsg, idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* remove RecipientEncryptedKeys */
+    if (GetSequence(pkiMsg, idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* KeyAgreeRecipientIdentifier is CHOICE of IssuerAndSerialNumber
+     * or [0] IMMPLICIT RecipientKeyIdentifier */
+    if ( (pkiMsgSz > (*idx + 1)) &&
+         (pkiMsg[*idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0)) ) {
+
+        /* try to get RecipientKeyIdentifier */
+        ret = wc_PKCS7_KariGetSubjectKeyIdentifier(kari, pkiMsg, pkiMsgSz,
+                                                   idx, recipFound);
+    } else {
+        /* try to get IssuerAndSerialNumber */
+        ret = wc_PKCS7_KariGetIssuerAndSerialNumber(kari, pkiMsg, pkiMsgSz,
+                                                    idx, recipFound);
+    }
+
+    /* if we don't have either option, malformed CMS */
+    if (ret != 0)
+        return ret;
+
+    /* remove EncryptedKey */
+    if ( (pkiMsgSz > (*idx + 1)) &&
+         (pkiMsg[(*idx)++] != ASN_OCTET_STRING) )
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* put encrypted CEK in decryptedKey buffer for now, decrypt later */
+    if (length > *encryptedKeySz)
+        return BUFFER_E;
+
+    XMEMCPY(encryptedKey, pkiMsg + (*idx), length);
+    *encryptedKeySz = length;
+    (*idx) += length;
+
+    return 0;
+}
+
+#endif /* HAVE_ECC */
+
+
+/* decode ASN.1 KeyAgreeRecipientInfo (kari), return 0 on success,
+ * < 0 on error */
+static int wc_PKCS7_DecodeKari(PKCS7* pkcs7, byte* pkiMsg, word32 pkiMsgSz,
+                               word32* idx, byte* decryptedKey,
+                               word32* decryptedKeySz, int* recipFound)
+{
+#ifdef HAVE_ECC
+    int ret, keySz;
+    int encryptedKeySz;
+    int direction = 0;
+    word32 keyAgreeOID, keyWrapOID;
+
+#ifdef WOLFSSL_SMALL_STACK
+    byte* encryptedKey;
+#else
+    byte encryptedKey[MAX_ENCRYPTED_KEY_SZ];
+#endif
+
+    WC_PKCS7_KARI* kari;
+
+    if (pkcs7 == NULL || pkcs7->singleCert == NULL ||
+        pkcs7->singleCertSz == 0 || pkiMsg == NULL ||
+        idx == NULL || decryptedKey == NULL || decryptedKeySz == NULL) {
+        return BAD_FUNC_ARG;
+    }
+
+    kari = wc_PKCS7_KariNew(pkcs7, WC_PKCS7_DECODE);
+    if (kari == NULL)
+        return MEMORY_E;
+
+#ifdef WOLFSSL_SMALL_STACK
+    encryptedKey = (byte*)XMALLOC(MAX_ENCRYPTED_KEY_SZ, NULL,
+                                  DYNAMIC_TYPE_PKCS7);
+    if (encryptedKey == NULL) {
+        wc_PKCS7_KariFree(kari);
+        return MEMORY_E;
+    }
+#endif
+    encryptedKeySz = MAX_ENCRYPTED_KEY_SZ;
+
+    /* parse cert and key */
+    ret = wc_PKCS7_KariParseRecipCert(kari, (byte*)pkcs7->singleCert,
+                                      pkcs7->singleCertSz, pkcs7->privateKey,
+                                      pkcs7->privateKeySz);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        return ret;
+    }
+
+    /* remove OriginatorIdentifierOrKey */
+    ret = wc_PKCS7_KariGetOriginatorIdentifierOrKey(kari, pkiMsg,
+                                                    pkiMsgSz, idx);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        #ifdef WOLFSSL_SMALL_STACK
+            XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+        #endif
+        return ret;
+    }
+
+    /* try and remove optional UserKeyingMaterial */
+    ret = wc_PKCS7_KariGetUserKeyingMaterial(kari, pkiMsg, pkiMsgSz, idx);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        #ifdef WOLFSSL_SMALL_STACK
+            XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+        #endif
+        return ret;
+    }
+
+    /* remove KeyEncryptionAlgorithmIdentifier */
+    ret = wc_PKCS7_KariGetKeyEncryptionAlgorithmId(kari, pkiMsg, pkiMsgSz,
+                                                   idx, &keyAgreeOID,
+                                                   &keyWrapOID);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        #ifdef WOLFSSL_SMALL_STACK
+            XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+        #endif
+        return ret;
+    }
+
+    /* set direction based on key wrap algorithm */
+    switch (keyWrapOID) {
+#ifndef NO_AES
+        case AES128_WRAP:
+        case AES192_WRAP:
+        case AES256_WRAP:
+            direction = AES_DECRYPTION;
+            break;
+#endif
+        default:
+            wc_PKCS7_KariFree(kari);
+            #ifdef WOLFSSL_SMALL_STACK
+                XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+            #endif
+            WOLFSSL_MSG("AES key wrap algorithm unsupported");
+            return BAD_KEYWRAP_ALG_E;
+    }
+
+    /* remove RecipientEncryptedKeys */
+    ret = wc_PKCS7_KariGetRecipientEncryptedKeys(kari, pkiMsg, pkiMsgSz,
+                               idx, recipFound, encryptedKey, &encryptedKeySz);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        #ifdef WOLFSSL_SMALL_STACK
+            XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+        #endif
+        return ret;
+    }
+
+    /* create KEK */
+    ret = wc_PKCS7_KariGenerateKEK(kari, keyWrapOID, pkcs7->keyAgreeOID);
+    if (ret != 0) {
+        wc_PKCS7_KariFree(kari);
+        #ifdef WOLFSSL_SMALL_STACK
+            XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+        #endif
+        return ret;
+    }
+
+    /* decrypt CEK with KEK */
+    keySz = wc_PKCS7_KariKeyWrap(encryptedKey, encryptedKeySz, kari->kek,
+                                 kari->kekSz, decryptedKey, *decryptedKeySz,
+                                 keyWrapOID, direction);
+    if (keySz <= 0) {
+        wc_PKCS7_KariFree(kari);
+        #ifdef WOLFSSL_SMALL_STACK
+            XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+        #endif
+        return keySz;
+    }
+    *decryptedKeySz = (word32)keySz;
+
+    wc_PKCS7_KariFree(kari);
+    #ifdef WOLFSSL_SMALL_STACK
+        XFREE(encryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+    #endif
+
+    return 0;
+#else
+    (void)pkcs7;
+    (void)pkiMsg;
+    (void)pkiMsgSz;
+    (void)idx;
+    (void)decryptedKey;
+    (void)decryptedKeySz;
+    (void)recipFound;
+
+    return NOT_COMPILED_IN;
+#endif /* HAVE_ECC */
+}
+
+
+/* decode ASN.1 RecipientInfos SET, return 0 on success, < 0 on error */
+static int wc_PKCS7_DecodeRecipientInfos(PKCS7* pkcs7, byte* pkiMsg,
+                            word32 pkiMsgSz, word32* idx, byte* decryptedKey,
+                            word32* decryptedKeySz, int* recipFound)
+{
+    word32 savedIdx;
+    int version, ret, length;
+
+    if (pkcs7 == NULL || pkiMsg == NULL || idx == NULL ||
+        decryptedKey == NULL || decryptedKeySz == NULL ||
+        recipFound == NULL) {
+        return BAD_FUNC_ARG;
+    }
+
+    savedIdx = *idx;
+
+    /* when looking for next recipient, use first sequence and version to
+     * indicate there is another, if not, move on */
+    while(*recipFound == 0) {
+
+        /* remove RecipientInfo, if we don't have a SEQUENCE, back up idx to
+         * last good saved one */
+        if (GetSequence(pkiMsg, idx, &length, pkiMsgSz) > 0) {
+
+            if (GetMyVersion(pkiMsg, idx, &version, pkiMsgSz) < 0) {
+                *idx = savedIdx;
+                break;
+            }
+
+            if (version != 0)
+                return ASN_VERSION_E;
+
+            /* found ktri */
+            ret = wc_PKCS7_DecodeKtri(pkcs7, pkiMsg, pkiMsgSz, idx,
+                                      decryptedKey, decryptedKeySz,
+                                      recipFound);
+            if (ret != 0)
+                return ret;
+        }
+        else {
+            /* kari is IMPLICIT[1] */
+            *idx = savedIdx;
+            if (pkiMsg[*idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 1)) {
+                (*idx)++;
+
+                if (GetLength(pkiMsg, idx, &length, pkiMsgSz) < 0)
+                    return ASN_PARSE_E;
+
+                if (GetMyVersion(pkiMsg, idx, &version, pkiMsgSz) < 0) {
+                    *idx = savedIdx;
+                    break;
+                }
+
+                if (version != 3)
+                    return ASN_VERSION_E;
+
+                /* found kari */
+                ret = wc_PKCS7_DecodeKari(pkcs7, pkiMsg, pkiMsgSz, idx,
+                                          decryptedKey, decryptedKeySz,
+                                          recipFound);
+                if (ret != 0)
+                    return ret;
+            }
+            else {
+                /* failed to find RecipientInfo, restore idx and continue */
+                *idx = savedIdx;
+                break;
+            }
+        }
+
+        /* update good idx */
+        savedIdx = *idx;
+    }
+
+    return 0;
+}
+
+
+/* unwrap and decrypt PKCS#7 envelopedData object, return decoded size */
+WOLFSSL_API int wc_PKCS7_DecodeEnvelopedData(PKCS7* pkcs7, byte* pkiMsg,
+                                         word32 pkiMsgSz, byte* output,
+                                         word32 outputSz)
+{
+    int recipFound = 0;
+    int ret, version, length;
+    word32 idx = 0;
+    word32 contentType, encOID;
+    word32 decryptedKeySz;
+
+    int expBlockSz, blockKeySz;
+    byte tmpIv[MAX_CONTENT_IV_SIZE];
+
+#ifdef WOLFSSL_SMALL_STACK
+    byte* decryptedKey;
+#else
+    byte decryptedKey[MAX_ENCRYPTED_KEY_SZ];
+#endif
+    int encryptedContentSz;
+    byte padLen;
+    byte* encryptedContent = NULL;
+
+    if (pkcs7 == NULL || pkcs7->singleCert == NULL ||
+        pkcs7->singleCertSz == 0 || pkcs7->privateKey == NULL ||
+        pkcs7->privateKeySz == 0)
+        return BAD_FUNC_ARG;
+
+    if (pkiMsg == NULL || pkiMsgSz == 0 ||
+        output == NULL || outputSz == 0)
+        return BAD_FUNC_ARG;
+
+    /* read past ContentInfo, verify type is envelopedData */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (contentType != ENVELOPED_DATA) {
+        WOLFSSL_MSG("PKCS#7 input not of type EnvelopedData");
+        return PKCS7_OID_E;
+    }
+
+    if (pkiMsg[idx++] != (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0))
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* remove EnvelopedData and version */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (GetMyVersion(pkiMsg, &idx, &version, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* TODO :: make this more accurate */
+    if ((pkcs7->publicKeyOID == RSAk && version != 0) ||
+        (pkcs7->publicKeyOID == ECDSAk && version != 2)) {
+        WOLFSSL_MSG("PKCS#7 envelopedData needs to be of version 0");
+        return ASN_VERSION_E;
+    }
+
+    /* walk through RecipientInfo set, find correct recipient */
+    if (GetSet(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+#ifdef WOLFSSL_SMALL_STACK
+    decryptedKey = (byte*)XMALLOC(MAX_ENCRYPTED_KEY_SZ, NULL,
+                                                       DYNAMIC_TYPE_PKCS7);
+    if (decryptedKey == NULL)
+        return MEMORY_E;
+#endif
+    decryptedKeySz = MAX_ENCRYPTED_KEY_SZ;
+
+    ret = wc_PKCS7_DecodeRecipientInfos(pkcs7, pkiMsg, pkiMsgSz, &idx,
+                                        decryptedKey, &decryptedKeySz,
+                                        &recipFound);
+    if (ret != 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ret;
+    }
+
+    if (recipFound == 0) {
+        WOLFSSL_MSG("No recipient found in envelopedData that matches input");
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return PKCS7_RECIP_E;
+    }
+
+    /* remove EncryptedContentInfo */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    if (GetAlgoId(pkiMsg, &idx, &encOID, oidBlkType, pkiMsgSz) < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    blockKeySz = wc_PKCS7_GetOIDKeySize(encOID);
+    if (blockKeySz < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return blockKeySz;
+    }
+
+    expBlockSz = wc_PKCS7_GetOIDBlockSize(encOID);
+    if (expBlockSz < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return expBlockSz;
+    }
+
+    /* get block cipher IV, stored in OPTIONAL parameter of AlgoID */
+    if (pkiMsg[idx++] != ASN_OCTET_STRING) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    if (length != expBlockSz) {
+        WOLFSSL_MSG("Incorrect IV length, must be of content alg block size");
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    XMEMCPY(tmpIv, &pkiMsg[idx], length);
+    idx += length;
+
+    /* read encryptedContent, cont[0] */
+    if (pkiMsg[idx++] != (ASN_CONTEXT_SPECIFIC | 0)) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    if (GetLength(pkiMsg, &idx, &encryptedContentSz, pkiMsgSz) <= 0) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ASN_PARSE_E;
+    }
+
+    encryptedContent = (byte*)XMALLOC(encryptedContentSz, pkcs7->heap,
+                                                       DYNAMIC_TYPE_PKCS7);
+    if (encryptedContent == NULL) {
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return MEMORY_E;
+    }
+
+    XMEMCPY(encryptedContent, &pkiMsg[idx], encryptedContentSz);
+
+    /* decrypt encryptedContent */
+    ret = wc_PKCS7_DecryptContent(encOID, decryptedKey, blockKeySz,
+                                  tmpIv, expBlockSz, encryptedContent,
+                                  encryptedContentSz, encryptedContent);
+    if (ret != 0) {
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+        return ret;
+    }
+
+    padLen = encryptedContent[encryptedContentSz-1];
+
+    /* copy plaintext to output */
+    XMEMCPY(output, encryptedContent, encryptedContentSz - padLen);
+
+    /* free memory, zero out keys */
+    ForceZero(decryptedKey, MAX_ENCRYPTED_KEY_SZ);
+    ForceZero(encryptedContent, encryptedContentSz);
+    XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7);
+#endif
+
+    return encryptedContentSz - padLen;
+}
+
+
+/* build PKCS#7 encryptedData content type, return encrypted size */
+int wc_PKCS7_EncodeEncryptedData(PKCS7* pkcs7, byte* output, word32 outputSz)
+{
+    int ret, idx = 0;
+    int totalSz, padSz, encryptedOutSz;
+
+    int contentInfoSeqSz, outerContentTypeSz, outerContentSz;
+    byte contentInfoSeq[MAX_SEQ_SZ];
+    byte outerContentType[MAX_ALGO_SZ];
+    byte outerContent[MAX_SEQ_SZ];
+
+    int encDataSeqSz, verSz, blockSz;
+    byte encDataSeq[MAX_SEQ_SZ];
+    byte ver[MAX_VERSION_SZ];
+
+    byte* plain = NULL;
+    byte* encryptedContent = NULL;
+
+    int encContentOctetSz, encContentSeqSz, contentTypeSz;
+    int contentEncAlgoSz, ivOctetStringSz;
+    byte encContentSeq[MAX_SEQ_SZ];
+    byte contentType[MAX_ALGO_SZ];
+    byte contentEncAlgo[MAX_ALGO_SZ];
+    byte tmpIv[MAX_CONTENT_IV_SIZE];
+    byte ivOctetString[MAX_OCTET_STR_SZ];
+    byte encContentOctet[MAX_OCTET_STR_SZ];
+
+    byte attribSet[MAX_SET_SZ];
+    EncodedAttrib* attribs = NULL;
+    word32 attribsSz;
+    word32 attribsCount;
+    word32 attribsSetSz;
+
+    byte* flatAttribs = NULL;
+
+    if (pkcs7 == NULL || pkcs7->content == NULL || pkcs7->contentSz == 0 ||
+        pkcs7->encryptOID == 0 || pkcs7->encryptionKey == NULL ||
+        pkcs7->encryptionKeySz == 0)
+        return BAD_FUNC_ARG;
+
+    if (output == NULL || outputSz == 0)
+        return BAD_FUNC_ARG;
+
+    /* outer content type */
+    outerContentTypeSz = wc_SetContentType(ENCRYPTED_DATA, outerContentType);
+
+    /* version, 2 if unprotectedAttrs present, 0 if absent */
+    if (pkcs7->unprotectedAttribsSz > 0) {
+        verSz = SetMyVersion(2, ver, 0);
+    } else {
+        verSz = SetMyVersion(0, ver, 0);
+    }
+
+    /* EncryptedContentInfo */
+    contentTypeSz = wc_SetContentType(pkcs7->contentOID, contentType);
+    if (contentTypeSz == 0)
+        return BAD_FUNC_ARG;
+
+    /* allocate encrypted content buffer, do PKCS#7 padding */
+    blockSz = wc_PKCS7_GetOIDBlockSize(pkcs7->encryptOID);
+    if (blockSz < 0)
+        return blockSz;
+
+    padSz = wc_PKCS7_GetPadSize(pkcs7->contentSz, blockSz);
+    if (padSz < 0)
+        return padSz;
+
+    encryptedOutSz = pkcs7->contentSz + padSz;
+
+    plain = (byte*)XMALLOC(encryptedOutSz, pkcs7->heap,
+                           DYNAMIC_TYPE_PKCS7);
+    if (plain == NULL)
+        return MEMORY_E;
+
+    ret = wc_PKCS7_PadData(pkcs7->content, pkcs7->contentSz, plain,
+                           encryptedOutSz, blockSz);
+    if (ret < 0) {
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return ret;
+    }
+
+    encryptedContent = (byte*)XMALLOC(encryptedOutSz, pkcs7->heap,
+                                      DYNAMIC_TYPE_PKCS7);
+    if (encryptedContent == NULL) {
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return MEMORY_E;
+    }
+
+    /* put together IV OCTET STRING */
+    ivOctetStringSz = SetOctetString(blockSz, ivOctetString);
+
+    /* build up ContentEncryptionAlgorithmIdentifier sequence,
+       adding (ivOctetStringSz + blockSz) for IV OCTET STRING */
+    contentEncAlgoSz = SetAlgoID(pkcs7->encryptOID, contentEncAlgo,
+                                 oidBlkType, ivOctetStringSz + blockSz);
+    if (contentEncAlgoSz == 0) {
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return BAD_FUNC_ARG;
+    }
+
+    /* encrypt content */
+    ret = wc_PKCS7_GenerateIV(pkcs7, NULL, tmpIv, blockSz);
+    if (ret != 0) {
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return ret;
+    }
+
+    ret = wc_PKCS7_EncryptContent(pkcs7->encryptOID, pkcs7->encryptionKey,
+            pkcs7->encryptionKeySz, tmpIv, blockSz, plain, encryptedOutSz,
+            encryptedContent);
+    if (ret != 0) {
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return ret;
+    }
+
+    encContentOctetSz = SetImplicit(ASN_OCTET_STRING, 0,
+                                    encryptedOutSz, encContentOctet);
+
+    encContentSeqSz = SetSequence(contentTypeSz + contentEncAlgoSz +
+                                  ivOctetStringSz + blockSz +
+                                  encContentOctetSz + encryptedOutSz,
+                                  encContentSeq);
+
+    /* optional UnprotectedAttributes */
+    if (pkcs7->unprotectedAttribsSz != 0) {
+
+        if (pkcs7->unprotectedAttribs == NULL) {
+            XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return BAD_FUNC_ARG;
+        }
+
+        attribs = (EncodedAttrib*)XMALLOC(
+                sizeof(EncodedAttrib) * pkcs7->unprotectedAttribsSz,
+                pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        if (attribs == NULL) {
+            XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return MEMORY_E;
+        }
+
+        attribsCount = pkcs7->unprotectedAttribsSz;
+        attribsSz = EncodeAttributes(attribs, pkcs7->unprotectedAttribsSz,
+                                     pkcs7->unprotectedAttribs,
+                                     pkcs7->unprotectedAttribsSz);
+
+        flatAttribs = (byte*)XMALLOC(attribsSz, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        if (flatAttribs == NULL) {
+            XFREE(attribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return MEMORY_E;
+        }
+
+        FlattenAttributes(flatAttribs, attribs, attribsCount);
+        attribsSetSz = SetImplicit(ASN_SET, 1, attribsSz, attribSet);
+
+    } else {
+        attribsSz = 0;
+        attribsSetSz = 0;
+    }
+
+    /* keep track of sizes for outer wrapper layering */
+    totalSz = verSz + encContentSeqSz + contentTypeSz + contentEncAlgoSz +
+              ivOctetStringSz + blockSz + encContentOctetSz + encryptedOutSz +
+              attribsSz + attribsSetSz;;
+
+    /* EncryptedData */
+    encDataSeqSz = SetSequence(totalSz, encDataSeq);
+    totalSz += encDataSeqSz;
+
+    /* outer content */
+    outerContentSz = SetExplicit(0, totalSz, outerContent);
+    totalSz += outerContentTypeSz;
+    totalSz += outerContentSz;
+
+    /* ContentInfo */
+    contentInfoSeqSz = SetSequence(totalSz, contentInfoSeq);
+    totalSz += contentInfoSeqSz;
+
+    if (totalSz > (int)outputSz) {
+        WOLFSSL_MSG("PKCS#7 output buffer too small");
+        if (pkcs7->unprotectedAttribsSz != 0) {
+            XFREE(attribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(flatAttribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        }
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return BUFFER_E;
+    }
+
+    XMEMCPY(output + idx, contentInfoSeq, contentInfoSeqSz);
+    idx += contentInfoSeqSz;
+    XMEMCPY(output + idx, outerContentType, outerContentTypeSz);
+    idx += outerContentTypeSz;
+    XMEMCPY(output + idx, outerContent, outerContentSz);
+    idx += outerContentSz;
+    XMEMCPY(output + idx, encDataSeq, encDataSeqSz);
+    idx += encDataSeqSz;
+    XMEMCPY(output + idx, ver, verSz);
+    idx += verSz;
+    XMEMCPY(output + idx, encContentSeq, encContentSeqSz);
+    idx += encContentSeqSz;
+    XMEMCPY(output + idx, contentType, contentTypeSz);
+    idx += contentTypeSz;
+    XMEMCPY(output + idx, contentEncAlgo, contentEncAlgoSz);
+    idx += contentEncAlgoSz;
+    XMEMCPY(output + idx, ivOctetString, ivOctetStringSz);
+    idx += ivOctetStringSz;
+    XMEMCPY(output + idx, tmpIv, blockSz);
+    idx += blockSz;
+    XMEMCPY(output + idx, encContentOctet, encContentOctetSz);
+    idx += encContentOctetSz;
+    XMEMCPY(output + idx, encryptedContent, encryptedOutSz);
+    idx += encryptedOutSz;
+
+    if (pkcs7->unprotectedAttribsSz != 0) {
+        XMEMCPY(output + idx, attribSet, attribsSetSz);
+        idx += attribsSetSz;
+        XMEMCPY(output + idx, flatAttribs, attribsSz);
+        idx += attribsSz;
+        XFREE(attribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        XFREE(flatAttribs, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+    }
+
+    XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+    XFREE(plain, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+
+    return idx;
+}
+
+
+/* decode and store unprotected attributes in PKCS7->decodedAttrib. Return
+ * 0 on success, negative on error. User must call wc_PKCS7_Free(). */
+static int wc_PKCS7_DecodeUnprotectedAttributes(PKCS7* pkcs7, byte* pkiMsg,
+                                             word32 pkiMsgSz, word32* inOutIdx)
+{
+    int length, attribLen;
+    word32 oid, savedIdx, idx;
+    PKCS7DecodedAttrib* attrib = NULL;
+
+    if (pkcs7 == NULL || pkiMsg == NULL ||
+        pkiMsgSz == 0 || inOutIdx == NULL)
+        return BAD_FUNC_ARG;
+
+    idx = *inOutIdx;
+
+    if (pkiMsg[idx] != (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 1))
+        return ASN_PARSE_E;
+    idx++;
+
+    if (GetLength(pkiMsg, &idx, &attribLen, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* loop through attributes */
+    while (attribLen > 0) {
+
+        if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+            return ASN_PARSE_E;
+
+        attribLen -= (length + 2); /* TAG + LENGTH + DATA */
+        savedIdx = idx;
+
+        attrib = (PKCS7DecodedAttrib*)XMALLOC(sizeof(PKCS7DecodedAttrib),
+                                              pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        if (attrib == NULL) {
+            return MEMORY_E;
+        }
+        XMEMSET(attrib, 0, sizeof(PKCS7DecodedAttrib));
+
+        /* save attribute OID bytes and size */
+        if (GetObjectId(pkiMsg, &idx, &oid, oidIgnoreType, pkiMsgSz) < 0) {
+            XFREE(attrib, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return ASN_PARSE_E;
+        }
+
+        attrib->oidSz = idx - savedIdx;
+        attrib->oid = (byte*)XMALLOC(attrib->oidSz, pkcs7->heap,
+                                     DYNAMIC_TYPE_PKCS7);
+        if (attrib->oid == NULL) {
+            XFREE(attrib, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return MEMORY_E;
+        }
+        XMEMCPY(attrib->oid, pkiMsg + savedIdx, attrib->oidSz);
+
+        /* save attribute value bytes and size */
+        if (GetSet(pkiMsg, &idx, &length, pkiMsgSz) < 0) {
+            XFREE(attrib->oid, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(attrib, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return ASN_PARSE_E;
+        }
+
+        if ((pkiMsgSz - idx) < (word32)length) {
+            XFREE(attrib->oid, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(attrib, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return ASN_PARSE_E;
+        }
+
+        attrib->valueSz = (word32)length;
+        attrib->value = (byte*)XMALLOC(attrib->valueSz, pkcs7->heap,
+                                       DYNAMIC_TYPE_PKCS7);
+        if (attrib->value == NULL) {
+            XFREE(attrib->oid, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            XFREE(attrib, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return MEMORY_E;
+        }
+        XMEMCPY(attrib->value, pkiMsg + idx, attrib->valueSz);
+        idx += length;
+
+        /* store attribute in linked list */
+        if (pkcs7->decodedAttrib != NULL) {
+            attrib->next = pkcs7->decodedAttrib;
+            pkcs7->decodedAttrib = attrib;
+        } else {
+            pkcs7->decodedAttrib = attrib;
+        }
+    }
+
+    *inOutIdx = idx;
+
+    return 0;
+}
+
+
+/* unwrap and decrypt PKCS#7/CMS encrypted-data object, returned decoded size */
+int wc_PKCS7_DecodeEncryptedData(PKCS7* pkcs7, byte* pkiMsg, word32 pkiMsgSz,
+                                 byte* output, word32 outputSz)
+{
+    int ret, version, length, haveAttribs;
+    word32 idx = 0;
+    word32 contentType, encOID;
+
+    int expBlockSz;
+    byte tmpIv[MAX_CONTENT_IV_SIZE];
+
+    int encryptedContentSz;
+    byte padLen;
+    byte* encryptedContent = NULL;
+
+    if (pkcs7 == NULL || pkcs7->encryptionKey == NULL ||
+        pkcs7->encryptionKeySz == 0)
+        return BAD_FUNC_ARG;
+
+    if (pkiMsg == NULL || pkiMsgSz == 0 ||
+        output == NULL || outputSz == 0)
+        return BAD_FUNC_ARG;
+
+    /* read past ContentInfo, verify type is encrypted-data */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (contentType != ENCRYPTED_DATA) {
+        WOLFSSL_MSG("PKCS#7 input not of type EncryptedData");
+        return PKCS7_OID_E;
+    }
+
+    if (pkiMsg[idx++] != (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0))
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* remove EncryptedData and version */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* get version, check later */
+    haveAttribs = 0;
+    if (GetMyVersion(pkiMsg, &idx, &version, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    /* remove EncryptedContentInfo */
+    if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (GetAlgoId(pkiMsg, &idx, &encOID, oidBlkType, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    expBlockSz = wc_PKCS7_GetOIDBlockSize(encOID);
+    if (expBlockSz < 0)
+        return expBlockSz;
+
+    /* get block cipher IV, stored in OPTIONAL parameter of AlgoID */
+    if (pkiMsg[idx++] != ASN_OCTET_STRING)
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, &idx, &length, pkiMsgSz) < 0)
+        return ASN_PARSE_E;
+
+    if (length != expBlockSz) {
+        WOLFSSL_MSG("Incorrect IV length, must be of content alg block size");
+        return ASN_PARSE_E;
+    }
+
+    XMEMCPY(tmpIv, &pkiMsg[idx], length);
+    idx += length;
+
+    /* read encryptedContent, cont[0] */
+    if (pkiMsg[idx++] != (ASN_CONTEXT_SPECIFIC | 0))
+        return ASN_PARSE_E;
+
+    if (GetLength(pkiMsg, &idx, &encryptedContentSz, pkiMsgSz) <= 0)
+        return ASN_PARSE_E;
+
+    encryptedContent = (byte*)XMALLOC(encryptedContentSz, pkcs7->heap,
+                                      DYNAMIC_TYPE_PKCS7);
+    if (encryptedContent == NULL)
+        return MEMORY_E;
+
+    XMEMCPY(encryptedContent, &pkiMsg[idx], encryptedContentSz);
+    idx += encryptedContentSz;
+
+    /* decrypt encryptedContent */
+    ret = wc_PKCS7_DecryptContent(encOID, pkcs7->encryptionKey,
+                                  pkcs7->encryptionKeySz, tmpIv, expBlockSz,
+                                  encryptedContent, encryptedContentSz,
+                                  encryptedContent);
+    if (ret != 0) {
+        XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+        return ret;
+    }
+
+    padLen = encryptedContent[encryptedContentSz-1];
+
+    /* copy plaintext to output */
+    XMEMCPY(output, encryptedContent, encryptedContentSz - padLen);
+
+    /* get implicit[1] unprotected attributes, optional */
+    pkcs7->decodedAttrib = NULL;
+    if (idx < pkiMsgSz) {
+
+        haveAttribs = 1;
+
+        ret = wc_PKCS7_DecodeUnprotectedAttributes(pkcs7, pkiMsg,
+                                                   pkiMsgSz, &idx);
+        if (ret != 0) {
+            ForceZero(encryptedContent, encryptedContentSz);
+            XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+            return ASN_PARSE_E;
+        }
+    }
+
+    /* go back and check the version now that attribs have been processed */
+    if ((haveAttribs == 0 && version != 0) ||
+        (haveAttribs == 1 && version != 2) ) {
+        WOLFSSL_MSG("Wrong PKCS#7 EncryptedData version");
+        return ASN_VERSION_E;
+    }
+
+    ForceZero(encryptedContent, encryptedContentSz);
+    XFREE(encryptedContent, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
+
+    return encryptedContentSz - padLen;
+}
+
+#else  /* HAVE_PKCS7 */
+
+
+#ifdef _MSC_VER
+    /* 4206 warning for blank file */
+    #pragma warning(disable: 4206)
+#endif
+
+
+#endif /* HAVE_PKCS7 */
+
+