Diff: wolfssl/wolfcrypt/srp.h

Revision:

13:f67a6c6013ca

Parent:

11:cee25a834751

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wolfssl/wolfcrypt/srp.h	Tue Aug 22 10:48:22 2017 +0000
@@ -0,0 +1,305 @@
+/* srp.h
+ *
+ * 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 WOLFCRYPT_HAVE_SRP
+
+#ifndef WOLFCRYPT_SRP_H
+#define WOLFCRYPT_SRP_H
+
+#include <wolfssl/wolfcrypt/types.h>
+#include <wolfssl/wolfcrypt/sha.h>
+#include <wolfssl/wolfcrypt/sha256.h>
+#include <wolfssl/wolfcrypt/sha512.h>
+#include <wolfssl/wolfcrypt/integer.h>
+
+#ifdef __cplusplus
+    extern "C" {
+#endif
+
+/* Select the largest available hash for the buffer size. */
+#if defined(WOLFSSL_SHA512)
+    #define SRP_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE
+#elif defined(WOLFSSL_SHA384)
+    #define SRP_MAX_DIGEST_SIZE SHA384_DIGEST_SIZE
+#elif !defined(NO_SHA256)
+    #define SRP_MAX_DIGEST_SIZE SHA256_DIGEST_SIZE
+#elif !defined(NO_SHA)
+    #define SRP_MAX_DIGEST_SIZE SHA_DIGEST_SIZE
+#else
+    #error "You have to have some kind of SHA hash if you want to use SRP."
+#endif
+
+/* Set the minimum number of bits acceptable in an SRP modulus */
+#define SRP_MODULUS_MIN_BITS 512
+
+/* Set the minimum number of bits acceptable for private keys (RFC 5054) */
+#define SRP_PRIVATE_KEY_MIN_BITS 256
+
+/**
+ * SRP side, client or server.
+ */
+typedef enum {
+    SRP_CLIENT_SIDE  = 0,
+    SRP_SERVER_SIDE  = 1,
+} SrpSide;
+
+/**
+ * SRP hash type, SHA[1|256|384|512].
+ */
+typedef enum {
+        SRP_TYPE_SHA    = 1,
+        SRP_TYPE_SHA256 = 2,
+        SRP_TYPE_SHA384 = 3,
+        SRP_TYPE_SHA512 = 4,
+} SrpType;
+
+/**
+ * SRP hash struct.
+ */
+typedef struct {
+    byte type;
+    union {
+        #ifndef NO_SHA
+            Sha sha;
+        #endif
+        #ifndef NO_SHA256
+            Sha256 sha256;
+        #endif
+        #ifdef WOLFSSL_SHA384
+            Sha384 sha384;
+        #endif
+        #ifdef WOLFSSL_SHA512
+            Sha512 sha512;
+        #endif
+    } data;
+} SrpHash;
+
+typedef struct Srp {
+    SrpSide side;                   /**< Client or Server, @see SrpSide.      */
+    SrpType type;                   /**< Hash type, @see SrpType.             */
+    byte*   user;                   /**< Username, login.                     */
+    word32  userSz;                 /**< Username length.                     */
+    byte*   salt;                   /**< Small salt.                          */
+    word32  saltSz;                 /**< Salt length.                         */
+    mp_int  N;                      /**< Modulus. N = 2q+1, [q, N] are primes.*/
+    mp_int  g;                      /**< Generator. A generator modulo N.     */
+    byte    k[SRP_MAX_DIGEST_SIZE]; /**< Multiplier parameter. k = H(N, g)   */
+    mp_int  auth;                   /**< Client: x = H(salt + H(user:pswd))   */
+                                    /**< Server: v = g ^ x % N                */
+    mp_int  priv;                   /**< Private ephemeral value.             */
+    SrpHash client_proof;           /**< Client proof. Sent to the Server.    */
+    SrpHash server_proof;           /**< Server proof. Sent to the Client.    */
+    byte*   key;                    /**< Session key.                         */
+    word32  keySz;                  /**< Session key length.                  */
+    int (*keyGenFunc_cb) (struct Srp* srp, byte* secret, word32 size);
+        /**< Function responsible for generating the session key.             */
+        /**< It MUST use XMALLOC with type DYNAMIC_TYPE_SRP to allocate the   */
+        /**< key buffer for this structure and set keySz to the buffer size.  */
+        /**< The default function used by this implementation is a modified   */
+        /**< version of t_mgf1 that uses the proper hash function according   */
+        /**< to srp->type.                                                    */
+    void*   heap;                   /**< heap hint pointer                    */
+} Srp;
+
+/**
+ * Initializes the Srp struct for usage.
+ *
+ * @param[out] srp   the Srp structure to be initialized.
+ * @param[in]  type  the hash type to be used.
+ * @param[in]  side  the side of the communication.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpInit(Srp* srp, SrpType type, SrpSide side);
+
+/**
+ * Releases the Srp struct resources after usage.
+ *
+ * @param[in,out] srp    the Srp structure to be terminated.
+ */
+WOLFSSL_API void wc_SrpTerm(Srp* srp);
+
+/**
+ * Sets the username.
+ *
+ * This function MUST be called after wc_SrpInit.
+ *
+ * @param[in,out] srp       the Srp structure.
+ * @param[in]     username  the buffer containing the username.
+ * @param[in]     size      the username size in bytes
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpSetUsername(Srp* srp, const byte* username, word32 size);
+
+
+/**
+ * Sets the srp parameters based on the username.
+ *
+ * This function MUST be called after wc_SrpSetUsername.
+ *
+ * @param[in,out] srp       the Srp structure.
+ * @param[in]     N         the Modulus. N = 2q+1, [q, N] are primes.
+ * @param[in]     nSz       the N size in bytes.
+ * @param[in]     g         the Generator modulo N.
+ * @param[in]     gSz       the g size in bytes
+ * @param[in]     salt      a small random salt. Specific for each username.
+ * @param[in]     saltSz    the salt size in bytes
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpSetParams(Srp* srp, const byte* N,    word32 nSz,
+                                          const byte* g,    word32 gSz,
+                                          const byte* salt, word32 saltSz);
+
+/**
+ * Sets the password.
+ *
+ * Setting the password does not persists the clear password data in the
+ * srp structure. The client calculates x = H(salt + H(user:pswd)) and stores
+ * it in the auth field.
+ *
+ * This function MUST be called after wc_SrpSetParams and is CLIENT SIDE ONLY.
+ *
+ * @param[in,out] srp       the Srp structure.
+ * @param[in]     password  the buffer containing the password.
+ * @param[in]     size      the password size in bytes.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpSetPassword(Srp* srp, const byte* password, word32 size);
+
+/**
+ * Sets the verifier.
+ *
+ * This function MUST be called after wc_SrpSetParams and is SERVER SIDE ONLY.
+ *
+ * @param[in,out] srp       the Srp structure.
+ * @param[in]     verifier  the buffer containing the verifier.
+ * @param[in]     size      the verifier size in bytes.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpSetVerifier(Srp* srp, const byte* verifier, word32 size);
+
+/**
+ * Gets the verifier.
+ *
+ * The client calculates the verifier with v = g ^ x % N.
+ * This function MAY be called after wc_SrpSetPassword and is CLIENT SIDE ONLY.
+ *
+ * @param[in,out] srp       the Srp structure.
+ * @param[out]    verifier  the buffer to write the verifier.
+ * @param[in,out] size      the buffer size in bytes. Will be updated with the
+ *                          verifier size.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpGetVerifier(Srp* srp, byte* verifier, word32* size);
+
+/**
+ * Sets the private ephemeral value.
+ *
+ * The private ephemeral value is known as:
+ *   a at the client side. a = random()
+ *   b at the server side. b = random()
+ * This function is handy for unit test cases or if the developer wants to use
+ * an external random source to set the ephemeral value.
+ * This function MAY be called before wc_SrpGetPublic.
+ *
+ * @param[in,out] srp       the Srp structure.
+ * @param[in]     priv      the ephemeral value.
+ * @param[in]     size      the private size in bytes.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpSetPrivate(Srp* srp, const byte* priv, word32 size);
+
+/**
+ * Gets the public ephemeral value.
+ *
+ * The public ephemeral value is known as:
+ *   A at the client side. A = g ^ a % N
+ *   B at the server side. B = (k * v + (g ˆ b % N)) % N
+ * This function MUST be called after wc_SrpSetPassword or wc_SrpSetVerifier.
+ *
+ * @param[in,out] srp       the Srp structure.
+ * @param[out]    pub       the buffer to write the public ephemeral value.
+ * @param[in,out] size      the the buffer size in bytes. Will be updated with
+ *                          the ephemeral value size.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpGetPublic(Srp* srp, byte* pub, word32* size);
+
+
+/**
+ * Computes the session key.
+ *
+ * The key can be accessed at srp->key after success.
+ *
+ * @param[in,out] srp               the Srp structure.
+ * @param[in]     clientPubKey      the client's public ephemeral value.
+ * @param[in]     clientPubKeySz    the client's public ephemeral value size.
+ * @param[in]     serverPubKey      the server's public ephemeral value.
+ * @param[in]     serverPubKeySz    the server's public ephemeral value size.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpComputeKey(Srp* srp,
+                                 byte* clientPubKey, word32 clientPubKeySz,
+                                 byte* serverPubKey, word32 serverPubKeySz);
+
+/**
+ * Gets the proof.
+ *
+ * This function MUST be called after wc_SrpComputeKey.
+ *
+ * @param[in,out] srp   the Srp structure.
+ * @param[out]    proof the buffer to write the proof.
+ * @param[in,out] size  the buffer size in bytes. Will be updated with the
+ *                          proof size.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpGetProof(Srp* srp, byte* proof, word32* size);
+
+/**
+ * Verifies the peers proof.
+ *
+ * This function MUST be called before wc_SrpGetSessionKey.
+ *
+ * @param[in,out] srp   the Srp structure.
+ * @param[in]     proof the peers proof.
+ * @param[in]     size  the proof size in bytes.
+ *
+ * @return 0 on success, {@literal <} 0 on error. @see error-crypt.h
+ */
+WOLFSSL_API int wc_SrpVerifyPeersProof(Srp* srp, byte* proof, word32 size);
+
+#ifdef __cplusplus
+   } /* extern "C" */
+#endif
+
+#endif /* WOLFCRYPT_SRP_H */
+#endif /* WOLFCRYPT_HAVE_SRP */
+