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cyclone_crypto/rsa.c@0:8918a71cdbe9, 2017-02-04 (annotated)

Committer:
Sergunb
Date:
Sat Feb 04 18:15:49 2017 +0000
Revision:
0:8918a71cdbe9
nothing else

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Sergunb 0:8918a71cdbe9 1 /**
Sergunb 0:8918a71cdbe9 2 * @file rsa.c
Sergunb 0:8918a71cdbe9 3 * @brief RSA public-key cryptography standard
Sergunb 0:8918a71cdbe9 4 *
Sergunb 0:8918a71cdbe9 5 * @section License
Sergunb 0:8918a71cdbe9 6 *
Sergunb 0:8918a71cdbe9 7 * Copyright (C) 2010-2017 Oryx Embedded SARL. All rights reserved.
Sergunb 0:8918a71cdbe9 8 *
Sergunb 0:8918a71cdbe9 9 * This file is part of CycloneCrypto Open.
Sergunb 0:8918a71cdbe9 10 *
Sergunb 0:8918a71cdbe9 11 * This program is free software; you can redistribute it and/or
Sergunb 0:8918a71cdbe9 12 * modify it under the terms of the GNU General Public License
Sergunb 0:8918a71cdbe9 13 * as published by the Free Software Foundation; either version 2
Sergunb 0:8918a71cdbe9 14 * of the License, or (at your option) any later version.
Sergunb 0:8918a71cdbe9 15 *
Sergunb 0:8918a71cdbe9 16 * This program is distributed in the hope that it will be useful,
Sergunb 0:8918a71cdbe9 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
Sergunb 0:8918a71cdbe9 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Sergunb 0:8918a71cdbe9 19 * GNU General Public License for more details.
Sergunb 0:8918a71cdbe9 20 *
Sergunb 0:8918a71cdbe9 21 * You should have received a copy of the GNU General Public License
Sergunb 0:8918a71cdbe9 22 * along with this program; if not, write to the Free Software Foundation,
Sergunb 0:8918a71cdbe9 23 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Sergunb 0:8918a71cdbe9 24 *
Sergunb 0:8918a71cdbe9 25 * @section Description
Sergunb 0:8918a71cdbe9 26 *
Sergunb 0:8918a71cdbe9 27 * RSA is an algorithm for public-key cryptography which is suitable for signing
Sergunb 0:8918a71cdbe9 28 * as well as encryption. Refer to PKCS #1 (RSA Cryptography Standard)
Sergunb 0:8918a71cdbe9 29 *
Sergunb 0:8918a71cdbe9 30 * @author Oryx Embedded SARL (www.oryx-embedded.com)
Sergunb 0:8918a71cdbe9 31 * @version 1.7.6
Sergunb 0:8918a71cdbe9 32 **/
Sergunb 0:8918a71cdbe9 33
Sergunb 0:8918a71cdbe9 34 //Switch to the appropriate trace level
Sergunb 0:8918a71cdbe9 35 #define TRACE_LEVEL CRYPTO_TRACE_LEVEL
Sergunb 0:8918a71cdbe9 36
Sergunb 0:8918a71cdbe9 37 //Dependencies
Sergunb 0:8918a71cdbe9 38 #include <stdlib.h>
Sergunb 0:8918a71cdbe9 39 #include <string.h>
Sergunb 0:8918a71cdbe9 40 #include "crypto.h"
Sergunb 0:8918a71cdbe9 41 #include "rsa.h"
Sergunb 0:8918a71cdbe9 42 #include "mpi.h"
Sergunb 0:8918a71cdbe9 43 #include "asn1.h"
Sergunb 0:8918a71cdbe9 44 #include "oid.h"
Sergunb 0:8918a71cdbe9 45 #include "debug.h"
Sergunb 0:8918a71cdbe9 46
Sergunb 0:8918a71cdbe9 47 //Check crypto library configuration
Sergunb 0:8918a71cdbe9 48 #if (RSA_SUPPORT == ENABLED)
Sergunb 0:8918a71cdbe9 49
Sergunb 0:8918a71cdbe9 50 //PKCS #1 OID (1.2.840.113549.1.1)
Sergunb 0:8918a71cdbe9 51 const uint8_t PKCS1_OID[8] = {0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01};
Sergunb 0:8918a71cdbe9 52 //RSA encryption OID (1.2.840.113549.1.1.1)
Sergunb 0:8918a71cdbe9 53 const uint8_t RSA_ENCRYPTION_OID[9] = {0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01};
Sergunb 0:8918a71cdbe9 54 //MD5 with RSA encryption OID (1.2.840.113549.1.1.4)
Sergunb 0:8918a71cdbe9 55 const uint8_t MD5_WITH_RSA_ENCRYPTION_OID[9] = {0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x04};
Sergunb 0:8918a71cdbe9 56 //SHA-1 with RSA encryption OID (1.2.840.113549.1.1.5)
Sergunb 0:8918a71cdbe9 57 const uint8_t SHA1_WITH_RSA_ENCRYPTION_OID[9] = {0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x05};
Sergunb 0:8918a71cdbe9 58 //SHA-256 with RSA encryption OID (1.2.840.113549.1.1.11)
Sergunb 0:8918a71cdbe9 59 const uint8_t SHA256_WITH_RSA_ENCRYPTION_OID[9] = {0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0B};
Sergunb 0:8918a71cdbe9 60 //SHA-384 with RSA encryption OID (1.2.840.113549.1.1.12)
Sergunb 0:8918a71cdbe9 61 const uint8_t SHA384_WITH_RSA_ENCRYPTION_OID[9] = {0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0C};
Sergunb 0:8918a71cdbe9 62 //SHA-512 with RSA encryption OID (1.2.840.113549.1.1.13)
Sergunb 0:8918a71cdbe9 63 const uint8_t SHA512_WITH_RSA_ENCRYPTION_OID[9] = {0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0D};
Sergunb 0:8918a71cdbe9 64 //RSA PKCS #1 v1.5 signature with SHA-3-224 OID (2.16.840.1.101.3.4.3.13)
Sergunb 0:8918a71cdbe9 65 const uint8_t RSASSA_PKCS1_v1_5_WITH_SHA3_224_OID[9] = {0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x0D};
Sergunb 0:8918a71cdbe9 66 //RSA PKCS #1 v1.5 signature with SHA-3-256 OID (2.16.840.1.101.3.4.3.14)
Sergunb 0:8918a71cdbe9 67 const uint8_t RSASSA_PKCS1_v1_5_WITH_SHA3_256_OID[9] = {0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x0E};
Sergunb 0:8918a71cdbe9 68 //RSA PKCS #1 v1.5 signature with SHA-3-384 OID (2.16.840.1.101.3.4.3.15)
Sergunb 0:8918a71cdbe9 69 const uint8_t RSASSA_PKCS1_v1_5_WITH_SHA3_384_OID[9] = {0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x0F};
Sergunb 0:8918a71cdbe9 70 //RSA PKCS #1 v1.5 signature with SHA-3-512 OID (2.16.840.1.101.3.4.3.16)
Sergunb 0:8918a71cdbe9 71 const uint8_t RSASSA_PKCS1_v1_5_WITH_SHA3_512_OID[9] = {0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x10};
Sergunb 0:8918a71cdbe9 72
Sergunb 0:8918a71cdbe9 73
Sergunb 0:8918a71cdbe9 74 /**
Sergunb 0:8918a71cdbe9 75 * @brief Initialize a RSA public key
Sergunb 0:8918a71cdbe9 76 * @param[in] key Pointer to the RSA public key to initialize
Sergunb 0:8918a71cdbe9 77 **/
Sergunb 0:8918a71cdbe9 78
Sergunb 0:8918a71cdbe9 79 void rsaInitPublicKey(RsaPublicKey *key)
Sergunb 0:8918a71cdbe9 80 {
Sergunb 0:8918a71cdbe9 81 //Initialize multiple precision integers
Sergunb 0:8918a71cdbe9 82 mpiInit(&key->n);
Sergunb 0:8918a71cdbe9 83 mpiInit(&key->e);
Sergunb 0:8918a71cdbe9 84 }
Sergunb 0:8918a71cdbe9 85
Sergunb 0:8918a71cdbe9 86
Sergunb 0:8918a71cdbe9 87 /**
Sergunb 0:8918a71cdbe9 88 * @brief Release a RSA public key
Sergunb 0:8918a71cdbe9 89 * @param[in] key Pointer to the RSA public key to free
Sergunb 0:8918a71cdbe9 90 **/
Sergunb 0:8918a71cdbe9 91
Sergunb 0:8918a71cdbe9 92 void rsaFreePublicKey(RsaPublicKey *key)
Sergunb 0:8918a71cdbe9 93 {
Sergunb 0:8918a71cdbe9 94 //Free multiple precision integers
Sergunb 0:8918a71cdbe9 95 mpiFree(&key->n);
Sergunb 0:8918a71cdbe9 96 mpiFree(&key->e);
Sergunb 0:8918a71cdbe9 97 }
Sergunb 0:8918a71cdbe9 98
Sergunb 0:8918a71cdbe9 99
Sergunb 0:8918a71cdbe9 100 /**
Sergunb 0:8918a71cdbe9 101 * @brief Initialize a RSA private key
Sergunb 0:8918a71cdbe9 102 * @param[in] key Pointer to the RSA private key to initialize
Sergunb 0:8918a71cdbe9 103 **/
Sergunb 0:8918a71cdbe9 104
Sergunb 0:8918a71cdbe9 105 void rsaInitPrivateKey(RsaPrivateKey *key)
Sergunb 0:8918a71cdbe9 106 {
Sergunb 0:8918a71cdbe9 107 //Initialize multiple precision integers
Sergunb 0:8918a71cdbe9 108 mpiInit(&key->n);
Sergunb 0:8918a71cdbe9 109 mpiInit(&key->e);
Sergunb 0:8918a71cdbe9 110 mpiInit(&key->d);
Sergunb 0:8918a71cdbe9 111 mpiInit(&key->p);
Sergunb 0:8918a71cdbe9 112 mpiInit(&key->q);
Sergunb 0:8918a71cdbe9 113 mpiInit(&key->dp);
Sergunb 0:8918a71cdbe9 114 mpiInit(&key->dq);
Sergunb 0:8918a71cdbe9 115 mpiInit(&key->qinv);
Sergunb 0:8918a71cdbe9 116 }
Sergunb 0:8918a71cdbe9 117
Sergunb 0:8918a71cdbe9 118
Sergunb 0:8918a71cdbe9 119 /**
Sergunb 0:8918a71cdbe9 120 * @brief Release a RSA private key
Sergunb 0:8918a71cdbe9 121 * @param[in] key Pointer to the RSA private key to free
Sergunb 0:8918a71cdbe9 122 **/
Sergunb 0:8918a71cdbe9 123
Sergunb 0:8918a71cdbe9 124 void rsaFreePrivateKey(RsaPrivateKey *key)
Sergunb 0:8918a71cdbe9 125 {
Sergunb 0:8918a71cdbe9 126 //Free multiple precision integers
Sergunb 0:8918a71cdbe9 127 mpiFree(&key->n);
Sergunb 0:8918a71cdbe9 128 mpiFree(&key->e);
Sergunb 0:8918a71cdbe9 129 mpiFree(&key->d);
Sergunb 0:8918a71cdbe9 130 mpiFree(&key->p);
Sergunb 0:8918a71cdbe9 131 mpiFree(&key->q);
Sergunb 0:8918a71cdbe9 132 mpiFree(&key->dp);
Sergunb 0:8918a71cdbe9 133 mpiFree(&key->dq);
Sergunb 0:8918a71cdbe9 134 mpiFree(&key->qinv);
Sergunb 0:8918a71cdbe9 135 }
Sergunb 0:8918a71cdbe9 136
Sergunb 0:8918a71cdbe9 137
Sergunb 0:8918a71cdbe9 138 /**
Sergunb 0:8918a71cdbe9 139 * @brief RSA encryption primitive
Sergunb 0:8918a71cdbe9 140 *
Sergunb 0:8918a71cdbe9 141 * The RSA encryption primitive produces a ciphertext representative from
Sergunb 0:8918a71cdbe9 142 * a message representative under the control of a public key
Sergunb 0:8918a71cdbe9 143 *
Sergunb 0:8918a71cdbe9 144 * @param[in] key RSA public key
Sergunb 0:8918a71cdbe9 145 * @param[in] m Message representative
Sergunb 0:8918a71cdbe9 146 * @param[out] c Ciphertext representative
Sergunb 0:8918a71cdbe9 147 * @return Error code
Sergunb 0:8918a71cdbe9 148 **/
Sergunb 0:8918a71cdbe9 149
Sergunb 0:8918a71cdbe9 150 error_t rsaep(const RsaPublicKey *key, const Mpi *m, Mpi *c)
Sergunb 0:8918a71cdbe9 151 {
Sergunb 0:8918a71cdbe9 152 //Ensure the RSA public key is valid
Sergunb 0:8918a71cdbe9 153 if(!key->n.size || !key->e.size)
Sergunb 0:8918a71cdbe9 154 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 155
Sergunb 0:8918a71cdbe9 156 //The message representative m shall be between 0 and n - 1
Sergunb 0:8918a71cdbe9 157 if(mpiCompInt(m, 0) < 0 || mpiComp(m, &key->n) >= 0)
Sergunb 0:8918a71cdbe9 158 return ERROR_OUT_OF_RANGE;
Sergunb 0:8918a71cdbe9 159
Sergunb 0:8918a71cdbe9 160 //Perform modular exponentiation (c = m ^ e mod n)
Sergunb 0:8918a71cdbe9 161 return mpiExpMod(c, m, &key->e, &key->n);
Sergunb 0:8918a71cdbe9 162 }
Sergunb 0:8918a71cdbe9 163
Sergunb 0:8918a71cdbe9 164
Sergunb 0:8918a71cdbe9 165 /**
Sergunb 0:8918a71cdbe9 166 * @brief RSA decryption primitive
Sergunb 0:8918a71cdbe9 167 *
Sergunb 0:8918a71cdbe9 168 * The RSA decryption primitive recovers the message representative from
Sergunb 0:8918a71cdbe9 169 * the ciphertext representative under the control of a private key
Sergunb 0:8918a71cdbe9 170 *
Sergunb 0:8918a71cdbe9 171 * @param[in] key RSA private key
Sergunb 0:8918a71cdbe9 172 * @param[in] c Ciphertext representative
Sergunb 0:8918a71cdbe9 173 * @param[out] m Message representative
Sergunb 0:8918a71cdbe9 174 * @return Error code
Sergunb 0:8918a71cdbe9 175 **/
Sergunb 0:8918a71cdbe9 176
Sergunb 0:8918a71cdbe9 177 error_t rsadp(const RsaPrivateKey *key, const Mpi *c, Mpi *m)
Sergunb 0:8918a71cdbe9 178 {
Sergunb 0:8918a71cdbe9 179 error_t error;
Sergunb 0:8918a71cdbe9 180 Mpi m1;
Sergunb 0:8918a71cdbe9 181 Mpi m2;
Sergunb 0:8918a71cdbe9 182 Mpi h;
Sergunb 0:8918a71cdbe9 183
Sergunb 0:8918a71cdbe9 184 //The ciphertext representative c shall be between 0 and n - 1
Sergunb 0:8918a71cdbe9 185 if(mpiCompInt(c, 0) < 0 || mpiComp(c, &key->n) >= 0)
Sergunb 0:8918a71cdbe9 186 return ERROR_OUT_OF_RANGE;
Sergunb 0:8918a71cdbe9 187
Sergunb 0:8918a71cdbe9 188 //Initialize multiple-precision integers
Sergunb 0:8918a71cdbe9 189 mpiInit(&m1);
Sergunb 0:8918a71cdbe9 190 mpiInit(&m2);
Sergunb 0:8918a71cdbe9 191 mpiInit(&h);
Sergunb 0:8918a71cdbe9 192
Sergunb 0:8918a71cdbe9 193 //Use the Chinese remainder algorithm?
Sergunb 0:8918a71cdbe9 194 if(key->n.size && key->p.size && key->q.size &&
Sergunb 0:8918a71cdbe9 195 key->dp.size && key->dq.size && key->qinv.size)
Sergunb 0:8918a71cdbe9 196 {
Sergunb 0:8918a71cdbe9 197 //Compute m1 = c ^ dP mod p
Sergunb 0:8918a71cdbe9 198 MPI_CHECK(mpiExpMod(&m1, c, &key->dp, &key->p));
Sergunb 0:8918a71cdbe9 199 //Compute m2 = c ^ dQ mod q
Sergunb 0:8918a71cdbe9 200 MPI_CHECK(mpiExpMod(&m2, c, &key->dq, &key->q));
Sergunb 0:8918a71cdbe9 201 //Let h = (m1 - m2) * qInv mod p
Sergunb 0:8918a71cdbe9 202 MPI_CHECK(mpiSub(&h, &m1, &m2));
Sergunb 0:8918a71cdbe9 203 MPI_CHECK(mpiMulMod(&h, &h, &key->qinv, &key->p));
Sergunb 0:8918a71cdbe9 204 //Let m = m2 + q * h
Sergunb 0:8918a71cdbe9 205 MPI_CHECK(mpiMul(m, &key->q, &h));
Sergunb 0:8918a71cdbe9 206 MPI_CHECK(mpiAdd(m, m, &m2));
Sergunb 0:8918a71cdbe9 207 }
Sergunb 0:8918a71cdbe9 208 //Use modular exponentiation?
Sergunb 0:8918a71cdbe9 209 else if(key->n.size && key->d.size)
Sergunb 0:8918a71cdbe9 210 {
Sergunb 0:8918a71cdbe9 211 //Let m = c ^ d mod n
Sergunb 0:8918a71cdbe9 212 error = mpiExpMod(m, c, &key->d, &key->n);
Sergunb 0:8918a71cdbe9 213 }
Sergunb 0:8918a71cdbe9 214 //Invalid parameters?
Sergunb 0:8918a71cdbe9 215 else
Sergunb 0:8918a71cdbe9 216 {
Sergunb 0:8918a71cdbe9 217 //Report an error
Sergunb 0:8918a71cdbe9 218 error = ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 219 }
Sergunb 0:8918a71cdbe9 220
Sergunb 0:8918a71cdbe9 221 end:
Sergunb 0:8918a71cdbe9 222 //Free previously allocated memory
Sergunb 0:8918a71cdbe9 223 mpiFree(&m1);
Sergunb 0:8918a71cdbe9 224 mpiFree(&m2);
Sergunb 0:8918a71cdbe9 225 mpiFree(&h);
Sergunb 0:8918a71cdbe9 226
Sergunb 0:8918a71cdbe9 227 //Return status code
Sergunb 0:8918a71cdbe9 228 return error;
Sergunb 0:8918a71cdbe9 229 }
Sergunb 0:8918a71cdbe9 230
Sergunb 0:8918a71cdbe9 231
Sergunb 0:8918a71cdbe9 232 /**
Sergunb 0:8918a71cdbe9 233 * @brief RSA signature primitive
Sergunb 0:8918a71cdbe9 234 *
Sergunb 0:8918a71cdbe9 235 * The RSA signature primitive produces a signature representative from
Sergunb 0:8918a71cdbe9 236 * a message representative under the control of a private key
Sergunb 0:8918a71cdbe9 237 *
Sergunb 0:8918a71cdbe9 238 * @param[in] key RSA private key
Sergunb 0:8918a71cdbe9 239 * @param[in] m Message representative
Sergunb 0:8918a71cdbe9 240 * @param[out] s Signature representative
Sergunb 0:8918a71cdbe9 241 * @return Error code
Sergunb 0:8918a71cdbe9 242 **/
Sergunb 0:8918a71cdbe9 243
Sergunb 0:8918a71cdbe9 244 error_t rsasp1(const RsaPrivateKey *key, const Mpi *m, Mpi *s)
Sergunb 0:8918a71cdbe9 245 {
Sergunb 0:8918a71cdbe9 246 //RSASP1 primitive is the same as RSADP except for the names of its
Sergunb 0:8918a71cdbe9 247 //input and output arguments. They are distinguished as they are
Sergunb 0:8918a71cdbe9 248 //intended for different purposes
Sergunb 0:8918a71cdbe9 249 return rsadp(key, m, s);
Sergunb 0:8918a71cdbe9 250 }
Sergunb 0:8918a71cdbe9 251
Sergunb 0:8918a71cdbe9 252
Sergunb 0:8918a71cdbe9 253 /**
Sergunb 0:8918a71cdbe9 254 * @brief RSA verification primitive
Sergunb 0:8918a71cdbe9 255 *
Sergunb 0:8918a71cdbe9 256 * The RSA verification primitive recovers the message representative from
Sergunb 0:8918a71cdbe9 257 * the signature representative under the control of a public key
Sergunb 0:8918a71cdbe9 258 *
Sergunb 0:8918a71cdbe9 259 * @param[in] key RSA public key
Sergunb 0:8918a71cdbe9 260 * @param[in] s Signature representative
Sergunb 0:8918a71cdbe9 261 * @param[out] m Message representative
Sergunb 0:8918a71cdbe9 262 * @return Error code
Sergunb 0:8918a71cdbe9 263 **/
Sergunb 0:8918a71cdbe9 264
Sergunb 0:8918a71cdbe9 265 error_t rsavp1(const RsaPublicKey *key, const Mpi *s, Mpi *m)
Sergunb 0:8918a71cdbe9 266 {
Sergunb 0:8918a71cdbe9 267 //RSAVP1 primitive is the same as RSAEP except for the names of its
Sergunb 0:8918a71cdbe9 268 //input and output arguments. They are distinguished as they are
Sergunb 0:8918a71cdbe9 269 //intended for different purposes
Sergunb 0:8918a71cdbe9 270 return rsaep(key, s, m);
Sergunb 0:8918a71cdbe9 271 }
Sergunb 0:8918a71cdbe9 272
Sergunb 0:8918a71cdbe9 273
Sergunb 0:8918a71cdbe9 274 /**
Sergunb 0:8918a71cdbe9 275 * @brief PKCS #1 v1.5 encryption operation
Sergunb 0:8918a71cdbe9 276 * @param[in] prngAlgo PRNG algorithm
Sergunb 0:8918a71cdbe9 277 * @param[in] prngContext Pointer to the PRNG context
Sergunb 0:8918a71cdbe9 278 * @param[in] key Recipient's RSA public key
Sergunb 0:8918a71cdbe9 279 * @param[in] message Message to be encrypted
Sergunb 0:8918a71cdbe9 280 * @param[in] messageLength Length of the message to be encrypted
Sergunb 0:8918a71cdbe9 281 * @param[out] ciphertext Ciphertext resulting from the encryption operation
Sergunb 0:8918a71cdbe9 282 * @param[out] ciphertextLength Length of the resulting ciphertext
Sergunb 0:8918a71cdbe9 283 * @return Error code
Sergunb 0:8918a71cdbe9 284 **/
Sergunb 0:8918a71cdbe9 285
Sergunb 0:8918a71cdbe9 286 error_t rsaesPkcs1v15Encrypt(const PrngAlgo *prngAlgo, void *prngContext, const RsaPublicKey *key,
Sergunb 0:8918a71cdbe9 287 const uint8_t *message, size_t messageLength, uint8_t *ciphertext, size_t *ciphertextLength)
Sergunb 0:8918a71cdbe9 288 {
Sergunb 0:8918a71cdbe9 289 error_t error;
Sergunb 0:8918a71cdbe9 290 uint_t i;
Sergunb 0:8918a71cdbe9 291 uint_t j;
Sergunb 0:8918a71cdbe9 292 uint_t k;
Sergunb 0:8918a71cdbe9 293 uint_t n;
Sergunb 0:8918a71cdbe9 294 uint8_t *p;
Sergunb 0:8918a71cdbe9 295 Mpi m;
Sergunb 0:8918a71cdbe9 296 Mpi c;
Sergunb 0:8918a71cdbe9 297
Sergunb 0:8918a71cdbe9 298 //Check parameters
Sergunb 0:8918a71cdbe9 299 if(key == NULL || message == NULL)
Sergunb 0:8918a71cdbe9 300 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 301 if(ciphertext == NULL || ciphertextLength == NULL)
Sergunb 0:8918a71cdbe9 302 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 303
Sergunb 0:8918a71cdbe9 304 //Debug message
Sergunb 0:8918a71cdbe9 305 TRACE_DEBUG("RSA PKCS #1 v1.5 encryption...\r\n");
Sergunb 0:8918a71cdbe9 306 TRACE_DEBUG(" Modulus:\r\n");
Sergunb 0:8918a71cdbe9 307 TRACE_DEBUG_MPI(" ", &key->n);
Sergunb 0:8918a71cdbe9 308 TRACE_DEBUG(" Public exponent:\r\n");
Sergunb 0:8918a71cdbe9 309 TRACE_DEBUG_MPI(" ", &key->e);
Sergunb 0:8918a71cdbe9 310 TRACE_DEBUG(" Message:\r\n");
Sergunb 0:8918a71cdbe9 311 TRACE_DEBUG_ARRAY(" ", message, messageLength);
Sergunb 0:8918a71cdbe9 312
Sergunb 0:8918a71cdbe9 313 //Initialize multiple-precision integers
Sergunb 0:8918a71cdbe9 314 mpiInit(&m);
Sergunb 0:8918a71cdbe9 315 mpiInit(&c);
Sergunb 0:8918a71cdbe9 316
Sergunb 0:8918a71cdbe9 317 //Get the length in octets of the modulus n
Sergunb 0:8918a71cdbe9 318 k = mpiGetByteLength(&key->n);
Sergunb 0:8918a71cdbe9 319
Sergunb 0:8918a71cdbe9 320 //Check the length of the message
Sergunb 0:8918a71cdbe9 321 if((messageLength + 11) > k)
Sergunb 0:8918a71cdbe9 322 return ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 323
Sergunb 0:8918a71cdbe9 324 //Point to the buffer where the encoded message EM will be formatted
Sergunb 0:8918a71cdbe9 325 p = ciphertext;
Sergunb 0:8918a71cdbe9 326
Sergunb 0:8918a71cdbe9 327 //The leading 0x00 octet ensures that the encoded message,
Sergunb 0:8918a71cdbe9 328 //converted to an integer, is less than the modulus
Sergunb 0:8918a71cdbe9 329 *(p++) = 0x00;
Sergunb 0:8918a71cdbe9 330 //For a public-key operation, the block type BT shall be 0x02
Sergunb 0:8918a71cdbe9 331 *(p++) = 0x02;
Sergunb 0:8918a71cdbe9 332
Sergunb 0:8918a71cdbe9 333 //Length of the padding string PS
Sergunb 0:8918a71cdbe9 334 n = k - messageLength - 3;
Sergunb 0:8918a71cdbe9 335
Sergunb 0:8918a71cdbe9 336 //Generate the padding string (pseudo-randomly generated non-zero octets)
Sergunb 0:8918a71cdbe9 337 while(n > 0)
Sergunb 0:8918a71cdbe9 338 {
Sergunb 0:8918a71cdbe9 339 //Generate random data
Sergunb 0:8918a71cdbe9 340 error = prngAlgo->read(prngContext, p, n);
Sergunb 0:8918a71cdbe9 341 //Any error to report?
Sergunb 0:8918a71cdbe9 342 if(error)
Sergunb 0:8918a71cdbe9 343 return error;
Sergunb 0:8918a71cdbe9 344
Sergunb 0:8918a71cdbe9 345 //Parse the resulting octet string
Sergunb 0:8918a71cdbe9 346 for(i = 0, j = 0; j < n; j++)
Sergunb 0:8918a71cdbe9 347 {
Sergunb 0:8918a71cdbe9 348 //Strip any byte with a value of zero
Sergunb 0:8918a71cdbe9 349 if(p[j] != 0)
Sergunb 0:8918a71cdbe9 350 p[i++] = p[j];
Sergunb 0:8918a71cdbe9 351 }
Sergunb 0:8918a71cdbe9 352
Sergunb 0:8918a71cdbe9 353 //Advance data pointer
Sergunb 0:8918a71cdbe9 354 p += i;
Sergunb 0:8918a71cdbe9 355 n -= i;
Sergunb 0:8918a71cdbe9 356 }
Sergunb 0:8918a71cdbe9 357
Sergunb 0:8918a71cdbe9 358 //Append a 0x00 octet to the padding string
Sergunb 0:8918a71cdbe9 359 *(p++) = 0x00;
Sergunb 0:8918a71cdbe9 360 //Copy the message to be encrypted
Sergunb 0:8918a71cdbe9 361 memcpy(p, message, messageLength);
Sergunb 0:8918a71cdbe9 362
Sergunb 0:8918a71cdbe9 363 //Rewind to the beginning of the encoded message
Sergunb 0:8918a71cdbe9 364 p = ciphertext;
Sergunb 0:8918a71cdbe9 365
Sergunb 0:8918a71cdbe9 366 //Debug message
Sergunb 0:8918a71cdbe9 367 TRACE_DEBUG(" Encoded message\r\n");
Sergunb 0:8918a71cdbe9 368 TRACE_DEBUG_ARRAY(" ", p, k);
Sergunb 0:8918a71cdbe9 369
Sergunb 0:8918a71cdbe9 370 //Start of exception handling block
Sergunb 0:8918a71cdbe9 371 do
Sergunb 0:8918a71cdbe9 372 {
Sergunb 0:8918a71cdbe9 373 //Convert the encoded message EM to an integer message representative m
Sergunb 0:8918a71cdbe9 374 error = mpiReadRaw(&m, p, k);
Sergunb 0:8918a71cdbe9 375 //Conversion failed?
Sergunb 0:8918a71cdbe9 376 if(error)
Sergunb 0:8918a71cdbe9 377 break;
Sergunb 0:8918a71cdbe9 378
Sergunb 0:8918a71cdbe9 379 //Apply the RSAEP encryption primitive
Sergunb 0:8918a71cdbe9 380 error = rsaep(key, &m, &c);
Sergunb 0:8918a71cdbe9 381 //Any error to report?
Sergunb 0:8918a71cdbe9 382 if(error)
Sergunb 0:8918a71cdbe9 383 break;
Sergunb 0:8918a71cdbe9 384
Sergunb 0:8918a71cdbe9 385 //Convert the ciphertext representative c to a ciphertext of length k octets
Sergunb 0:8918a71cdbe9 386 error = mpiWriteRaw(&c, ciphertext, k);
Sergunb 0:8918a71cdbe9 387 //Conversion failed?
Sergunb 0:8918a71cdbe9 388 if(error)
Sergunb 0:8918a71cdbe9 389 break;
Sergunb 0:8918a71cdbe9 390
Sergunb 0:8918a71cdbe9 391 //Length of the resulting ciphertext
Sergunb 0:8918a71cdbe9 392 *ciphertextLength = k;
Sergunb 0:8918a71cdbe9 393
Sergunb 0:8918a71cdbe9 394 //Debug message
Sergunb 0:8918a71cdbe9 395 TRACE_DEBUG(" Ciphertext:\r\n");
Sergunb 0:8918a71cdbe9 396 TRACE_DEBUG_ARRAY(" ", ciphertext, *ciphertextLength);
Sergunb 0:8918a71cdbe9 397
Sergunb 0:8918a71cdbe9 398 //End of exception handling block
Sergunb 0:8918a71cdbe9 399 } while(0);
Sergunb 0:8918a71cdbe9 400
Sergunb 0:8918a71cdbe9 401 //Free previously allocated memory
Sergunb 0:8918a71cdbe9 402 mpiFree(&m);
Sergunb 0:8918a71cdbe9 403 mpiFree(&c);
Sergunb 0:8918a71cdbe9 404
Sergunb 0:8918a71cdbe9 405 //Return status code
Sergunb 0:8918a71cdbe9 406 return error;
Sergunb 0:8918a71cdbe9 407 }
Sergunb 0:8918a71cdbe9 408
Sergunb 0:8918a71cdbe9 409
Sergunb 0:8918a71cdbe9 410 /**
Sergunb 0:8918a71cdbe9 411 * @brief PKCS #1 v1.5 decryption operation
Sergunb 0:8918a71cdbe9 412 * @param[in] key Recipient's RSA private key
Sergunb 0:8918a71cdbe9 413 * @param[in] ciphertext Ciphertext to be decrypted
Sergunb 0:8918a71cdbe9 414 * @param[in] ciphertextLength Length of the ciphertext to be decrypted
Sergunb 0:8918a71cdbe9 415 * @param[out] message Output buffer where to store the decrypted message
Sergunb 0:8918a71cdbe9 416 * @param[in] messageSize Size of the output buffer
Sergunb 0:8918a71cdbe9 417 * @param[out] messageLength Length of the decrypted message
Sergunb 0:8918a71cdbe9 418 * @return Error code
Sergunb 0:8918a71cdbe9 419 **/
Sergunb 0:8918a71cdbe9 420
Sergunb 0:8918a71cdbe9 421 error_t rsaesPkcs1v15Decrypt(const RsaPrivateKey *key, const uint8_t *ciphertext,
Sergunb 0:8918a71cdbe9 422 size_t ciphertextLength, uint8_t *message, size_t messageSize, size_t *messageLength)
Sergunb 0:8918a71cdbe9 423 {
Sergunb 0:8918a71cdbe9 424 error_t error;
Sergunb 0:8918a71cdbe9 425 uint_t i;
Sergunb 0:8918a71cdbe9 426 uint_t k;
Sergunb 0:8918a71cdbe9 427 uint8_t *em;
Sergunb 0:8918a71cdbe9 428 Mpi c;
Sergunb 0:8918a71cdbe9 429 Mpi m;
Sergunb 0:8918a71cdbe9 430
Sergunb 0:8918a71cdbe9 431 //Check parameters
Sergunb 0:8918a71cdbe9 432 if(key == NULL || ciphertext == NULL)
Sergunb 0:8918a71cdbe9 433 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 434 if(message == NULL || messageLength == NULL)
Sergunb 0:8918a71cdbe9 435 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 436
Sergunb 0:8918a71cdbe9 437 //Debug message
Sergunb 0:8918a71cdbe9 438 TRACE_DEBUG("RSA PKCS #1 v1.5 decryption...\r\n");
Sergunb 0:8918a71cdbe9 439 TRACE_DEBUG(" Modulus:\r\n");
Sergunb 0:8918a71cdbe9 440 TRACE_DEBUG_MPI(" ", &key->n);
Sergunb 0:8918a71cdbe9 441 TRACE_DEBUG(" Public exponent:\r\n");
Sergunb 0:8918a71cdbe9 442 TRACE_DEBUG_MPI(" ", &key->e);
Sergunb 0:8918a71cdbe9 443 TRACE_DEBUG(" Private exponent:\r\n");
Sergunb 0:8918a71cdbe9 444 TRACE_DEBUG_MPI(" ", &key->d);
Sergunb 0:8918a71cdbe9 445 TRACE_DEBUG(" Prime 1:\r\n");
Sergunb 0:8918a71cdbe9 446 TRACE_DEBUG_MPI(" ", &key->p);
Sergunb 0:8918a71cdbe9 447 TRACE_DEBUG(" Prime 2:\r\n");
Sergunb 0:8918a71cdbe9 448 TRACE_DEBUG_MPI(" ", &key->q);
Sergunb 0:8918a71cdbe9 449 TRACE_DEBUG(" Prime exponent 1:\r\n");
Sergunb 0:8918a71cdbe9 450 TRACE_DEBUG_MPI(" ", &key->dp);
Sergunb 0:8918a71cdbe9 451 TRACE_DEBUG(" Prime exponent 2:\r\n");
Sergunb 0:8918a71cdbe9 452 TRACE_DEBUG_MPI(" ", &key->dq);
Sergunb 0:8918a71cdbe9 453 TRACE_DEBUG(" Coefficient:\r\n");
Sergunb 0:8918a71cdbe9 454 TRACE_DEBUG_MPI(" ", &key->qinv);
Sergunb 0:8918a71cdbe9 455 TRACE_DEBUG(" Ciphertext:\r\n");
Sergunb 0:8918a71cdbe9 456 TRACE_DEBUG_ARRAY(" ", ciphertext, ciphertextLength);
Sergunb 0:8918a71cdbe9 457
Sergunb 0:8918a71cdbe9 458 //Initialize multiple-precision integers
Sergunb 0:8918a71cdbe9 459 mpiInit(&c);
Sergunb 0:8918a71cdbe9 460 mpiInit(&m);
Sergunb 0:8918a71cdbe9 461
Sergunb 0:8918a71cdbe9 462 //Get the length in octets of the modulus n
Sergunb 0:8918a71cdbe9 463 k = mpiGetByteLength(&key->n);
Sergunb 0:8918a71cdbe9 464
Sergunb 0:8918a71cdbe9 465 //Check the length of the ciphertext
Sergunb 0:8918a71cdbe9 466 if(ciphertextLength != k || ciphertextLength < 11)
Sergunb 0:8918a71cdbe9 467 return ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 468
Sergunb 0:8918a71cdbe9 469 //Allocate a buffer to store the encoded message EM
Sergunb 0:8918a71cdbe9 470 em = cryptoAllocMem(k);
Sergunb 0:8918a71cdbe9 471 //Failed to allocate memory?
Sergunb 0:8918a71cdbe9 472 if(em == NULL)
Sergunb 0:8918a71cdbe9 473 return ERROR_OUT_OF_MEMORY;
Sergunb 0:8918a71cdbe9 474
Sergunb 0:8918a71cdbe9 475 //Start of exception handling block
Sergunb 0:8918a71cdbe9 476 do
Sergunb 0:8918a71cdbe9 477 {
Sergunb 0:8918a71cdbe9 478 //Convert the ciphertext to an integer ciphertext representative c
Sergunb 0:8918a71cdbe9 479 error = mpiReadRaw(&c, ciphertext, ciphertextLength);
Sergunb 0:8918a71cdbe9 480 //Conversion failed?
Sergunb 0:8918a71cdbe9 481 if(error)
Sergunb 0:8918a71cdbe9 482 break;
Sergunb 0:8918a71cdbe9 483
Sergunb 0:8918a71cdbe9 484 //Apply the RSADP decryption primitive
Sergunb 0:8918a71cdbe9 485 error = rsadp(key, &c, &m);
Sergunb 0:8918a71cdbe9 486 //Any error to report?
Sergunb 0:8918a71cdbe9 487 if(error)
Sergunb 0:8918a71cdbe9 488 break;
Sergunb 0:8918a71cdbe9 489
Sergunb 0:8918a71cdbe9 490 //Convert the message representative m to an encoded message EM of length k octets
Sergunb 0:8918a71cdbe9 491 error = mpiWriteRaw(&m, em, k);
Sergunb 0:8918a71cdbe9 492 //Conversion failed?
Sergunb 0:8918a71cdbe9 493 if(error)
Sergunb 0:8918a71cdbe9 494 break;
Sergunb 0:8918a71cdbe9 495
Sergunb 0:8918a71cdbe9 496 //Debug message
Sergunb 0:8918a71cdbe9 497 TRACE_DEBUG(" Encoded message\r\n");
Sergunb 0:8918a71cdbe9 498 TRACE_DEBUG_ARRAY(" ", em, k);
Sergunb 0:8918a71cdbe9 499
Sergunb 0:8918a71cdbe9 500 //The first octet of EM must have a value of 0x00
Sergunb 0:8918a71cdbe9 501 //and the block type BT shall be 0x02
Sergunb 0:8918a71cdbe9 502 if(em[0] != 0x00 || em[1] != 0x02)
Sergunb 0:8918a71cdbe9 503 {
Sergunb 0:8918a71cdbe9 504 //Report an error
Sergunb 0:8918a71cdbe9 505 error = ERROR_UNEXPECTED_VALUE;
Sergunb 0:8918a71cdbe9 506 break;
Sergunb 0:8918a71cdbe9 507 }
Sergunb 0:8918a71cdbe9 508
Sergunb 0:8918a71cdbe9 509 //An octet with hexadecimal value 0x00 is used to separate PS from M
Sergunb 0:8918a71cdbe9 510 for(i = 2; i < k && em[i] != 0x00; i++);
Sergunb 0:8918a71cdbe9 511
Sergunb 0:8918a71cdbe9 512 //Check whether the padding string is valid
Sergunb 0:8918a71cdbe9 513 if(i < 10 || i >= k)
Sergunb 0:8918a71cdbe9 514 {
Sergunb 0:8918a71cdbe9 515 //Report an error
Sergunb 0:8918a71cdbe9 516 error = ERROR_INVALID_PADDING;
Sergunb 0:8918a71cdbe9 517 break;
Sergunb 0:8918a71cdbe9 518 }
Sergunb 0:8918a71cdbe9 519
Sergunb 0:8918a71cdbe9 520 //Ensure that the output buffer is large enough
Sergunb 0:8918a71cdbe9 521 if(messageSize < (k - i - 1))
Sergunb 0:8918a71cdbe9 522 {
Sergunb 0:8918a71cdbe9 523 //Report an error
Sergunb 0:8918a71cdbe9 524 error = ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 525 break;
Sergunb 0:8918a71cdbe9 526 }
Sergunb 0:8918a71cdbe9 527
Sergunb 0:8918a71cdbe9 528 //Recover the length of the message
Sergunb 0:8918a71cdbe9 529 *messageLength = k - i - 1;
Sergunb 0:8918a71cdbe9 530 //Copy the message contents
Sergunb 0:8918a71cdbe9 531 memcpy(message, em + i + 1, *messageLength);
Sergunb 0:8918a71cdbe9 532
Sergunb 0:8918a71cdbe9 533 //Debug message
Sergunb 0:8918a71cdbe9 534 TRACE_DEBUG(" Message:\r\n");
Sergunb 0:8918a71cdbe9 535 TRACE_DEBUG_ARRAY(" ", message, *messageLength);
Sergunb 0:8918a71cdbe9 536
Sergunb 0:8918a71cdbe9 537 //End of exception handling block
Sergunb 0:8918a71cdbe9 538 } while(0);
Sergunb 0:8918a71cdbe9 539
Sergunb 0:8918a71cdbe9 540 //Release multiple precision integers
Sergunb 0:8918a71cdbe9 541 mpiFree(&c);
Sergunb 0:8918a71cdbe9 542 mpiFree(&m);
Sergunb 0:8918a71cdbe9 543 //Free previously allocated memory
Sergunb 0:8918a71cdbe9 544 cryptoFreeMem(em);
Sergunb 0:8918a71cdbe9 545
Sergunb 0:8918a71cdbe9 546 //Return status code
Sergunb 0:8918a71cdbe9 547 return error;
Sergunb 0:8918a71cdbe9 548 }
Sergunb 0:8918a71cdbe9 549
Sergunb 0:8918a71cdbe9 550
Sergunb 0:8918a71cdbe9 551 /**
Sergunb 0:8918a71cdbe9 552 * @brief PKCS #1 v1.5 signature generation operation
Sergunb 0:8918a71cdbe9 553 * @param[in] key Signer's RSA private key
Sergunb 0:8918a71cdbe9 554 * @param[in] hash Hash function used to digest the message
Sergunb 0:8918a71cdbe9 555 * @param[in] digest Digest of the message to be signed
Sergunb 0:8918a71cdbe9 556 * @param[out] signature Resulting signature
Sergunb 0:8918a71cdbe9 557 * @param[out] signatureLength Length of the resulting signature
Sergunb 0:8918a71cdbe9 558 * @return Error code
Sergunb 0:8918a71cdbe9 559 **/
Sergunb 0:8918a71cdbe9 560
Sergunb 0:8918a71cdbe9 561 error_t rsassaPkcs1v15Sign(const RsaPrivateKey *key, const HashAlgo *hash,
Sergunb 0:8918a71cdbe9 562 const uint8_t *digest, uint8_t *signature, size_t *signatureLength)
Sergunb 0:8918a71cdbe9 563 {
Sergunb 0:8918a71cdbe9 564 error_t error;
Sergunb 0:8918a71cdbe9 565 uint_t k;
Sergunb 0:8918a71cdbe9 566 uint8_t *em;
Sergunb 0:8918a71cdbe9 567 Mpi m;
Sergunb 0:8918a71cdbe9 568 Mpi s;
Sergunb 0:8918a71cdbe9 569
Sergunb 0:8918a71cdbe9 570 //Check parameters
Sergunb 0:8918a71cdbe9 571 if(key == NULL || hash == NULL || digest == NULL)
Sergunb 0:8918a71cdbe9 572 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 573 if(signature == NULL || signatureLength == NULL)
Sergunb 0:8918a71cdbe9 574 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 575
Sergunb 0:8918a71cdbe9 576 //Debug message
Sergunb 0:8918a71cdbe9 577 TRACE_DEBUG("RSA PKCS #1 v1.5 signature generation...\r\n");
Sergunb 0:8918a71cdbe9 578 TRACE_DEBUG(" Modulus:\r\n");
Sergunb 0:8918a71cdbe9 579 TRACE_DEBUG_MPI(" ", &key->n);
Sergunb 0:8918a71cdbe9 580 TRACE_DEBUG(" Public exponent:\r\n");
Sergunb 0:8918a71cdbe9 581 TRACE_DEBUG_MPI(" ", &key->e);
Sergunb 0:8918a71cdbe9 582 TRACE_DEBUG(" Private exponent:\r\n");
Sergunb 0:8918a71cdbe9 583 TRACE_DEBUG_MPI(" ", &key->d);
Sergunb 0:8918a71cdbe9 584 TRACE_DEBUG(" Prime 1:\r\n");
Sergunb 0:8918a71cdbe9 585 TRACE_DEBUG_MPI(" ", &key->p);
Sergunb 0:8918a71cdbe9 586 TRACE_DEBUG(" Prime 2:\r\n");
Sergunb 0:8918a71cdbe9 587 TRACE_DEBUG_MPI(" ", &key->q);
Sergunb 0:8918a71cdbe9 588 TRACE_DEBUG(" Prime exponent 1:\r\n");
Sergunb 0:8918a71cdbe9 589 TRACE_DEBUG_MPI(" ", &key->dp);
Sergunb 0:8918a71cdbe9 590 TRACE_DEBUG(" Prime exponent 2:\r\n");
Sergunb 0:8918a71cdbe9 591 TRACE_DEBUG_MPI(" ", &key->dq);
Sergunb 0:8918a71cdbe9 592 TRACE_DEBUG(" Coefficient:\r\n");
Sergunb 0:8918a71cdbe9 593 TRACE_DEBUG_MPI(" ", &key->qinv);
Sergunb 0:8918a71cdbe9 594 TRACE_DEBUG(" Message digest:\r\n");
Sergunb 0:8918a71cdbe9 595 TRACE_DEBUG_ARRAY(" ", digest, hash->digestSize);
Sergunb 0:8918a71cdbe9 596
Sergunb 0:8918a71cdbe9 597 //Initialize multiple-precision integers
Sergunb 0:8918a71cdbe9 598 mpiInit(&m);
Sergunb 0:8918a71cdbe9 599 mpiInit(&s);
Sergunb 0:8918a71cdbe9 600
Sergunb 0:8918a71cdbe9 601 //Get the length in octets of the modulus n
Sergunb 0:8918a71cdbe9 602 k = mpiGetByteLength(&key->n);
Sergunb 0:8918a71cdbe9 603 //Point to the buffer where the encoded message EM will be generated
Sergunb 0:8918a71cdbe9 604 em = signature;
Sergunb 0:8918a71cdbe9 605
Sergunb 0:8918a71cdbe9 606 //Apply the EMSA-PKCS1-v1.5 encoding operation
Sergunb 0:8918a71cdbe9 607 error = emsaPkcs1v15Encode(hash, digest, em, k);
Sergunb 0:8918a71cdbe9 608 //Any error to report?
Sergunb 0:8918a71cdbe9 609 if(error)
Sergunb 0:8918a71cdbe9 610 return error;
Sergunb 0:8918a71cdbe9 611
Sergunb 0:8918a71cdbe9 612 //Debug message
Sergunb 0:8918a71cdbe9 613 TRACE_DEBUG(" Encoded message\r\n");
Sergunb 0:8918a71cdbe9 614 TRACE_DEBUG_ARRAY(" ", em, k);
Sergunb 0:8918a71cdbe9 615
Sergunb 0:8918a71cdbe9 616 //Start of exception handling block
Sergunb 0:8918a71cdbe9 617 do
Sergunb 0:8918a71cdbe9 618 {
Sergunb 0:8918a71cdbe9 619 //Convert the encoded message EM to an integer message representative m
Sergunb 0:8918a71cdbe9 620 error = mpiReadRaw(&m, em, k);
Sergunb 0:8918a71cdbe9 621 //Conversion failed?
Sergunb 0:8918a71cdbe9 622 if(error)
Sergunb 0:8918a71cdbe9 623 break;
Sergunb 0:8918a71cdbe9 624
Sergunb 0:8918a71cdbe9 625 //Apply the RSASP1 signature primitive
Sergunb 0:8918a71cdbe9 626 error = rsasp1(key, &m, &s);
Sergunb 0:8918a71cdbe9 627 //Any error to report?
Sergunb 0:8918a71cdbe9 628 if(error)
Sergunb 0:8918a71cdbe9 629 break;
Sergunb 0:8918a71cdbe9 630
Sergunb 0:8918a71cdbe9 631 //Convert the signature representative s to a signature of length k octets
Sergunb 0:8918a71cdbe9 632 error = mpiWriteRaw(&s, signature, k);
Sergunb 0:8918a71cdbe9 633 //Conversion failed?
Sergunb 0:8918a71cdbe9 634 if(error)
Sergunb 0:8918a71cdbe9 635 break;
Sergunb 0:8918a71cdbe9 636
Sergunb 0:8918a71cdbe9 637 //Length of the resulting signature
Sergunb 0:8918a71cdbe9 638 *signatureLength = k;
Sergunb 0:8918a71cdbe9 639
Sergunb 0:8918a71cdbe9 640 //Debug message
Sergunb 0:8918a71cdbe9 641 TRACE_DEBUG(" Signature:\r\n");
Sergunb 0:8918a71cdbe9 642 TRACE_DEBUG_ARRAY(" ", signature, *signatureLength);
Sergunb 0:8918a71cdbe9 643
Sergunb 0:8918a71cdbe9 644 //End of exception handling block
Sergunb 0:8918a71cdbe9 645 } while(0);
Sergunb 0:8918a71cdbe9 646
Sergunb 0:8918a71cdbe9 647 //Free previously allocated memory
Sergunb 0:8918a71cdbe9 648 mpiFree(&m);
Sergunb 0:8918a71cdbe9 649 mpiFree(&s);
Sergunb 0:8918a71cdbe9 650
Sergunb 0:8918a71cdbe9 651 //Return status code
Sergunb 0:8918a71cdbe9 652 return error;
Sergunb 0:8918a71cdbe9 653 }
Sergunb 0:8918a71cdbe9 654
Sergunb 0:8918a71cdbe9 655
Sergunb 0:8918a71cdbe9 656 /**
Sergunb 0:8918a71cdbe9 657 * @brief PKCS #1 v1.5 signature verification operation
Sergunb 0:8918a71cdbe9 658 * @param[in] key Signer's RSA public key
Sergunb 0:8918a71cdbe9 659 * @param[in] hash Hash function used to digest the message
Sergunb 0:8918a71cdbe9 660 * @param[in] digest Digest of the message whose signature is to be verified
Sergunb 0:8918a71cdbe9 661 * @param[in] signature Signature to be verified
Sergunb 0:8918a71cdbe9 662 * @param[in] signatureLength Length of the signature to be verified
Sergunb 0:8918a71cdbe9 663 * @return Error code
Sergunb 0:8918a71cdbe9 664 **/
Sergunb 0:8918a71cdbe9 665
Sergunb 0:8918a71cdbe9 666 error_t rsassaPkcs1v15Verify(const RsaPublicKey *key, const HashAlgo *hash,
Sergunb 0:8918a71cdbe9 667 const uint8_t *digest, const uint8_t *signature, size_t signatureLength)
Sergunb 0:8918a71cdbe9 668 {
Sergunb 0:8918a71cdbe9 669 error_t error;
Sergunb 0:8918a71cdbe9 670 uint_t k;
Sergunb 0:8918a71cdbe9 671 uint8_t *em;
Sergunb 0:8918a71cdbe9 672 const uint8_t *oid;
Sergunb 0:8918a71cdbe9 673 size_t oidLength;
Sergunb 0:8918a71cdbe9 674 const uint8_t *d;
Sergunb 0:8918a71cdbe9 675 size_t dLength;
Sergunb 0:8918a71cdbe9 676 Mpi s;
Sergunb 0:8918a71cdbe9 677 Mpi m;
Sergunb 0:8918a71cdbe9 678
Sergunb 0:8918a71cdbe9 679 //Check parameters
Sergunb 0:8918a71cdbe9 680 if(key == NULL || hash == NULL || digest == NULL || signature == NULL)
Sergunb 0:8918a71cdbe9 681 return ERROR_INVALID_PARAMETER;
Sergunb 0:8918a71cdbe9 682
Sergunb 0:8918a71cdbe9 683 //Debug message
Sergunb 0:8918a71cdbe9 684 TRACE_DEBUG("RSA PKCS #1 v1.5 signature verification...\r\n");
Sergunb 0:8918a71cdbe9 685 TRACE_DEBUG(" Modulus:\r\n");
Sergunb 0:8918a71cdbe9 686 TRACE_DEBUG_MPI(" ", &key->n);
Sergunb 0:8918a71cdbe9 687 TRACE_DEBUG(" Public exponent:\r\n");
Sergunb 0:8918a71cdbe9 688 TRACE_DEBUG_MPI(" ", &key->e);
Sergunb 0:8918a71cdbe9 689 TRACE_DEBUG(" Message digest:\r\n");
Sergunb 0:8918a71cdbe9 690 TRACE_DEBUG_ARRAY(" ", digest, hash->digestSize);
Sergunb 0:8918a71cdbe9 691 TRACE_DEBUG(" Signature:\r\n");
Sergunb 0:8918a71cdbe9 692 TRACE_DEBUG_ARRAY(" ", signature, signatureLength);
Sergunb 0:8918a71cdbe9 693
Sergunb 0:8918a71cdbe9 694 //Initialize multiple-precision integers
Sergunb 0:8918a71cdbe9 695 mpiInit(&s);
Sergunb 0:8918a71cdbe9 696 mpiInit(&m);
Sergunb 0:8918a71cdbe9 697
Sergunb 0:8918a71cdbe9 698 //Get the length in octets of the modulus n
Sergunb 0:8918a71cdbe9 699 k = mpiGetByteLength(&key->n);
Sergunb 0:8918a71cdbe9 700
Sergunb 0:8918a71cdbe9 701 //Check the length of the signature
Sergunb 0:8918a71cdbe9 702 if(signatureLength != k)
Sergunb 0:8918a71cdbe9 703 return ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 704
Sergunb 0:8918a71cdbe9 705 //Allocate a memory buffer to hold the encoded message
Sergunb 0:8918a71cdbe9 706 em = cryptoAllocMem(k);
Sergunb 0:8918a71cdbe9 707 //Failed to allocate memory?
Sergunb 0:8918a71cdbe9 708 if(em == NULL)
Sergunb 0:8918a71cdbe9 709 return ERROR_OUT_OF_MEMORY;
Sergunb 0:8918a71cdbe9 710
Sergunb 0:8918a71cdbe9 711 //Start of exception handling block
Sergunb 0:8918a71cdbe9 712 do
Sergunb 0:8918a71cdbe9 713 {
Sergunb 0:8918a71cdbe9 714 //Convert the signature to an integer signature representative s
Sergunb 0:8918a71cdbe9 715 error = mpiReadRaw(&s, signature, signatureLength);
Sergunb 0:8918a71cdbe9 716 //Conversion failed?
Sergunb 0:8918a71cdbe9 717 if(error)
Sergunb 0:8918a71cdbe9 718 break;
Sergunb 0:8918a71cdbe9 719
Sergunb 0:8918a71cdbe9 720 //Apply the RSAVP1 verification primitive
Sergunb 0:8918a71cdbe9 721 error = rsavp1(key, &s, &m);
Sergunb 0:8918a71cdbe9 722 //Any error to report?
Sergunb 0:8918a71cdbe9 723 if(error)
Sergunb 0:8918a71cdbe9 724 break;
Sergunb 0:8918a71cdbe9 725
Sergunb 0:8918a71cdbe9 726 //Convert the message representative m to an encoded message EM of length k octets
Sergunb 0:8918a71cdbe9 727 error = mpiWriteRaw(&m, em, k);
Sergunb 0:8918a71cdbe9 728 //Conversion failed?
Sergunb 0:8918a71cdbe9 729 if(error)
Sergunb 0:8918a71cdbe9 730 break;
Sergunb 0:8918a71cdbe9 731
Sergunb 0:8918a71cdbe9 732 //Debug message
Sergunb 0:8918a71cdbe9 733 TRACE_DEBUG(" Encoded message\r\n");
Sergunb 0:8918a71cdbe9 734 TRACE_DEBUG_ARRAY(" ", em, k);
Sergunb 0:8918a71cdbe9 735
Sergunb 0:8918a71cdbe9 736 //Parse the encoded message EM
Sergunb 0:8918a71cdbe9 737 error = emsaPkcs1v15Decode(em, k, &oid, &oidLength, &d, &dLength);
Sergunb 0:8918a71cdbe9 738 //Any error to report?
Sergunb 0:8918a71cdbe9 739 if(error)
Sergunb 0:8918a71cdbe9 740 break;
Sergunb 0:8918a71cdbe9 741
Sergunb 0:8918a71cdbe9 742 //Assume an error...
Sergunb 0:8918a71cdbe9 743 error = ERROR_INVALID_SIGNATURE_ALGO;
Sergunb 0:8918a71cdbe9 744 //Ensure the hash algorithm identifier matches the OID
Sergunb 0:8918a71cdbe9 745 if(oidComp(oid, oidLength, hash->oid, hash->oidSize))
Sergunb 0:8918a71cdbe9 746 break;
Sergunb 0:8918a71cdbe9 747 //Check the length of the digest
Sergunb 0:8918a71cdbe9 748 if(dLength != hash->digestSize)
Sergunb 0:8918a71cdbe9 749 break;
Sergunb 0:8918a71cdbe9 750
Sergunb 0:8918a71cdbe9 751 //Compare the message digest
Sergunb 0:8918a71cdbe9 752 error = memcmp(digest, d, dLength) ? ERROR_INVALID_SIGNATURE : NO_ERROR;
Sergunb 0:8918a71cdbe9 753
Sergunb 0:8918a71cdbe9 754 //End of exception handling block
Sergunb 0:8918a71cdbe9 755 } while(0);
Sergunb 0:8918a71cdbe9 756
Sergunb 0:8918a71cdbe9 757 //Release multiple precision integers
Sergunb 0:8918a71cdbe9 758 mpiFree(&s);
Sergunb 0:8918a71cdbe9 759 mpiFree(&m);
Sergunb 0:8918a71cdbe9 760 //Free previously allocated memory
Sergunb 0:8918a71cdbe9 761 cryptoFreeMem(em);
Sergunb 0:8918a71cdbe9 762
Sergunb 0:8918a71cdbe9 763 //Return status code
Sergunb 0:8918a71cdbe9 764 return error;
Sergunb 0:8918a71cdbe9 765 }
Sergunb 0:8918a71cdbe9 766
Sergunb 0:8918a71cdbe9 767
Sergunb 0:8918a71cdbe9 768 /**
Sergunb 0:8918a71cdbe9 769 * @brief PKCS #1 v1.5 encoding method
Sergunb 0:8918a71cdbe9 770 * @param[in] hash Hash function used to digest the message
Sergunb 0:8918a71cdbe9 771 * @param[in] digest Digest of the message to be signed
Sergunb 0:8918a71cdbe9 772 * @param[out] em Encoded message
Sergunb 0:8918a71cdbe9 773 * @param[in] emLength Intended length of the encoded message
Sergunb 0:8918a71cdbe9 774 * @return Error code
Sergunb 0:8918a71cdbe9 775 **/
Sergunb 0:8918a71cdbe9 776
Sergunb 0:8918a71cdbe9 777 error_t emsaPkcs1v15Encode(const HashAlgo *hash,
Sergunb 0:8918a71cdbe9 778 const uint8_t *digest, uint8_t *em, size_t emLength)
Sergunb 0:8918a71cdbe9 779 {
Sergunb 0:8918a71cdbe9 780 uint_t i;
Sergunb 0:8918a71cdbe9 781 size_t paddingLength;
Sergunb 0:8918a71cdbe9 782
Sergunb 0:8918a71cdbe9 783 //Ensure the length of the digest is valid
Sergunb 0:8918a71cdbe9 784 if((hash->oidSize + hash->digestSize + 21) > emLength)
Sergunb 0:8918a71cdbe9 785 return ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 786
Sergunb 0:8918a71cdbe9 787 //The leading 0x00 octet ensures that the encoded message,
Sergunb 0:8918a71cdbe9 788 //converted to an integer, is less than the modulus
Sergunb 0:8918a71cdbe9 789 em[0] = 0x00;
Sergunb 0:8918a71cdbe9 790 //Block type 0x01 is used for private-key operations
Sergunb 0:8918a71cdbe9 791 em[1] = 0x01;
Sergunb 0:8918a71cdbe9 792
Sergunb 0:8918a71cdbe9 793 //Compute the length of the padding string PS
Sergunb 0:8918a71cdbe9 794 paddingLength = emLength - hash->oidSize - hash->digestSize - 13;
Sergunb 0:8918a71cdbe9 795 //Fill the padding string with 0xFF
Sergunb 0:8918a71cdbe9 796 memset(em + 2, 0xFF, paddingLength);
Sergunb 0:8918a71cdbe9 797
Sergunb 0:8918a71cdbe9 798 //Point to the byte that follows PS
Sergunb 0:8918a71cdbe9 799 i = paddingLength + 2;
Sergunb 0:8918a71cdbe9 800 //Append a 0x00 octet to PS
Sergunb 0:8918a71cdbe9 801 em[i++] = 0x00;
Sergunb 0:8918a71cdbe9 802
Sergunb 0:8918a71cdbe9 803 //Encode the DigestInfo using ASN.1
Sergunb 0:8918a71cdbe9 804 em[i++] = ASN1_ENCODING_CONSTRUCTED | ASN1_TYPE_SEQUENCE;
Sergunb 0:8918a71cdbe9 805 em[i++] = (uint8_t) (hash->oidSize + hash->digestSize + 8);
Sergunb 0:8918a71cdbe9 806 em[i++] = ASN1_ENCODING_CONSTRUCTED | ASN1_TYPE_SEQUENCE;
Sergunb 0:8918a71cdbe9 807 em[i++] = (uint8_t) (hash->oidSize + 4);
Sergunb 0:8918a71cdbe9 808 em[i++] = ASN1_TYPE_OBJECT_IDENTIFIER;
Sergunb 0:8918a71cdbe9 809 em[i++] = (uint8_t) hash->oidSize;
Sergunb 0:8918a71cdbe9 810
Sergunb 0:8918a71cdbe9 811 //Copy the hash algorithm OID
Sergunb 0:8918a71cdbe9 812 memcpy(em + i, hash->oid, hash->oidSize);
Sergunb 0:8918a71cdbe9 813 i += hash->oidSize;
Sergunb 0:8918a71cdbe9 814
Sergunb 0:8918a71cdbe9 815 //Encode the rest of the ASN.1 structure
Sergunb 0:8918a71cdbe9 816 em[i++] = ASN1_TYPE_NULL;
Sergunb 0:8918a71cdbe9 817 em[i++] = 0;
Sergunb 0:8918a71cdbe9 818 em[i++] = ASN1_TYPE_OCTET_STRING;
Sergunb 0:8918a71cdbe9 819 em[i++] = (uint8_t) hash->digestSize;
Sergunb 0:8918a71cdbe9 820
Sergunb 0:8918a71cdbe9 821 //Append the hash value
Sergunb 0:8918a71cdbe9 822 memcpy(em + i, digest, hash->digestSize);
Sergunb 0:8918a71cdbe9 823
Sergunb 0:8918a71cdbe9 824 //Successful processing
Sergunb 0:8918a71cdbe9 825 return NO_ERROR;
Sergunb 0:8918a71cdbe9 826 }
Sergunb 0:8918a71cdbe9 827
Sergunb 0:8918a71cdbe9 828
Sergunb 0:8918a71cdbe9 829 /**
Sergunb 0:8918a71cdbe9 830 * @brief PKCS #1 v1.5 decoding method
Sergunb 0:8918a71cdbe9 831 * @param[in] em Encoded message
Sergunb 0:8918a71cdbe9 832 * @param[in] emLength Length of the encoded message
Sergunb 0:8918a71cdbe9 833 * @param[out] oid Hash algorithm OID
Sergunb 0:8918a71cdbe9 834 * @param[out] oidLength Length of the hash algorithm OID
Sergunb 0:8918a71cdbe9 835 * @param[out] digest Digest value
Sergunb 0:8918a71cdbe9 836 * @param[out] digestLength Length of the digest value
Sergunb 0:8918a71cdbe9 837
Sergunb 0:8918a71cdbe9 838 * @return Error code
Sergunb 0:8918a71cdbe9 839 **/
Sergunb 0:8918a71cdbe9 840
Sergunb 0:8918a71cdbe9 841 error_t emsaPkcs1v15Decode(const uint8_t *em, size_t emLength, const uint8_t **oid,
Sergunb 0:8918a71cdbe9 842 size_t *oidLength, const uint8_t **digest, size_t *digestLength)
Sergunb 0:8918a71cdbe9 843 {
Sergunb 0:8918a71cdbe9 844 error_t error;
Sergunb 0:8918a71cdbe9 845 uint_t i;
Sergunb 0:8918a71cdbe9 846 size_t length;
Sergunb 0:8918a71cdbe9 847 const uint8_t *data;
Sergunb 0:8918a71cdbe9 848 Asn1Tag tag;
Sergunb 0:8918a71cdbe9 849
Sergunb 0:8918a71cdbe9 850 //Check the length of the encoded message EM
Sergunb 0:8918a71cdbe9 851 if(emLength < 11)
Sergunb 0:8918a71cdbe9 852 return ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 853
Sergunb 0:8918a71cdbe9 854 //The first octet of EM must have a value of 0x00
Sergunb 0:8918a71cdbe9 855 if(em[0] != 0x00)
Sergunb 0:8918a71cdbe9 856 return ERROR_UNEXPECTED_VALUE;
Sergunb 0:8918a71cdbe9 857 //The block type BT shall be 0x01
Sergunb 0:8918a71cdbe9 858 if(em[1] != 0x01)
Sergunb 0:8918a71cdbe9 859 return ERROR_UNEXPECTED_VALUE;
Sergunb 0:8918a71cdbe9 860
Sergunb 0:8918a71cdbe9 861 //Check the padding string PS
Sergunb 0:8918a71cdbe9 862 for(i = 2; i < emLength; i++)
Sergunb 0:8918a71cdbe9 863 {
Sergunb 0:8918a71cdbe9 864 //A 0x00 octet indicates the end of the padding string
Sergunb 0:8918a71cdbe9 865 if(em[i] == 0x00)
Sergunb 0:8918a71cdbe9 866 break;
Sergunb 0:8918a71cdbe9 867 //Each byte of PS must be set to 0xFF when the block type is 0x01
Sergunb 0:8918a71cdbe9 868 if(em[i] != 0xFF)
Sergunb 0:8918a71cdbe9 869 return ERROR_INVALID_PADDING;
Sergunb 0:8918a71cdbe9 870 }
Sergunb 0:8918a71cdbe9 871
Sergunb 0:8918a71cdbe9 872 //Check whether the padding string is properly terminated
Sergunb 0:8918a71cdbe9 873 if(i >= emLength)
Sergunb 0:8918a71cdbe9 874 return ERROR_INVALID_PADDING;
Sergunb 0:8918a71cdbe9 875 //The length of PS cannot be less than 8 octets
Sergunb 0:8918a71cdbe9 876 if(i < 10)
Sergunb 0:8918a71cdbe9 877 return ERROR_INVALID_PADDING;
Sergunb 0:8918a71cdbe9 878
Sergunb 0:8918a71cdbe9 879 //Point to the DigestInfo structure
Sergunb 0:8918a71cdbe9 880 data = em + i + 1;
Sergunb 0:8918a71cdbe9 881 length = emLength - i - 1;
Sergunb 0:8918a71cdbe9 882
Sergunb 0:8918a71cdbe9 883 //Read the contents of the DigestInfo structure
Sergunb 0:8918a71cdbe9 884 error = asn1ReadTag(data, length, &tag);
Sergunb 0:8918a71cdbe9 885 //Failed to decode the ASN.1 tag?
Sergunb 0:8918a71cdbe9 886 if(error)
Sergunb 0:8918a71cdbe9 887 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 888
Sergunb 0:8918a71cdbe9 889 //Enforce encoding, class and type
Sergunb 0:8918a71cdbe9 890 if(!tag.constructed || tag.objType != ASN1_TYPE_SEQUENCE)
Sergunb 0:8918a71cdbe9 891 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 892
Sergunb 0:8918a71cdbe9 893 //Point to the DigestAlgorithm structure
Sergunb 0:8918a71cdbe9 894 data = tag.value;
Sergunb 0:8918a71cdbe9 895 length = tag.length;
Sergunb 0:8918a71cdbe9 896
Sergunb 0:8918a71cdbe9 897 //Decode the DigestAlgorithm tag
Sergunb 0:8918a71cdbe9 898 error = asn1ReadTag(data, length, &tag);
Sergunb 0:8918a71cdbe9 899 //Failed to decode the ASN.1 tag?
Sergunb 0:8918a71cdbe9 900 if(error)
Sergunb 0:8918a71cdbe9 901 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 902
Sergunb 0:8918a71cdbe9 903 //Enforce encoding, class and type
Sergunb 0:8918a71cdbe9 904 if(!tag.constructed || tag.objType != ASN1_TYPE_SEQUENCE)
Sergunb 0:8918a71cdbe9 905 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 906
Sergunb 0:8918a71cdbe9 907 //Save the location of the next tag
Sergunb 0:8918a71cdbe9 908 data += tag.totalLength;
Sergunb 0:8918a71cdbe9 909 length -= tag.totalLength;
Sergunb 0:8918a71cdbe9 910
Sergunb 0:8918a71cdbe9 911 //Decode the AlgorithmIdentifier tag
Sergunb 0:8918a71cdbe9 912 error = asn1ReadTag(tag.value, tag.length, &tag);
Sergunb 0:8918a71cdbe9 913 //Failed to decode the ASN.1 tag?
Sergunb 0:8918a71cdbe9 914 if(error)
Sergunb 0:8918a71cdbe9 915 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 916
Sergunb 0:8918a71cdbe9 917 //Enforce encoding, class and type
Sergunb 0:8918a71cdbe9 918 if(tag.constructed || tag.objType != ASN1_TYPE_OBJECT_IDENTIFIER)
Sergunb 0:8918a71cdbe9 919 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 920
Sergunb 0:8918a71cdbe9 921 //Save the hash algorithm OID
Sergunb 0:8918a71cdbe9 922 *oid = tag.value;
Sergunb 0:8918a71cdbe9 923 *oidLength = tag.length;
Sergunb 0:8918a71cdbe9 924
Sergunb 0:8918a71cdbe9 925 //Decode the DigestValue tag
Sergunb 0:8918a71cdbe9 926 error = asn1ReadTag(data, length, &tag);
Sergunb 0:8918a71cdbe9 927 //Failed to decode the ASN.1 tag?
Sergunb 0:8918a71cdbe9 928 if(error)
Sergunb 0:8918a71cdbe9 929 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 930
Sergunb 0:8918a71cdbe9 931 //Enforce encoding, class and type
Sergunb 0:8918a71cdbe9 932 if(tag.constructed || tag.objType != ASN1_TYPE_OCTET_STRING)
Sergunb 0:8918a71cdbe9 933 return ERROR_INVALID_TAG;
Sergunb 0:8918a71cdbe9 934
Sergunb 0:8918a71cdbe9 935 //Save the hash value
Sergunb 0:8918a71cdbe9 936 *digest = tag.value;
Sergunb 0:8918a71cdbe9 937 *digestLength = tag.length;
Sergunb 0:8918a71cdbe9 938
Sergunb 0:8918a71cdbe9 939 //EM successfully decoded
Sergunb 0:8918a71cdbe9 940 return NO_ERROR;
Sergunb 0:8918a71cdbe9 941 }
Sergunb 0:8918a71cdbe9 942
Sergunb 0:8918a71cdbe9 943 #endif
Sergunb 0:8918a71cdbe9 944