Sergey Pastor / 1

Webserver+3d print

Dependents:   Nucleo

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

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

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sergunb 0:8918a71cdbe9 1 /**
Sergunb 0:8918a71cdbe9 2 * @file cipher_mode_cbc.c
Sergunb 0:8918a71cdbe9 3 * @brief Cipher Block Chaining (CBC) mode
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 * The Cipher Block Chaining (CBC) mode is a confidentiality mode whose
Sergunb 0:8918a71cdbe9 28 * encryption process features the combining of the plaintext blocks with
Sergunb 0:8918a71cdbe9 29 * the previous ciphertext blocks. The CBC mode requires an IV to combine
Sergunb 0:8918a71cdbe9 30 * with the first plaintext block. Refer to SP 800-38A for more details
Sergunb 0:8918a71cdbe9 31 *
Sergunb 0:8918a71cdbe9 32 * @author Oryx Embedded SARL (www.oryx-embedded.com)
Sergunb 0:8918a71cdbe9 33 * @version 1.7.6
Sergunb 0:8918a71cdbe9 34 **/
Sergunb 0:8918a71cdbe9 35
Sergunb 0:8918a71cdbe9 36 //Switch to the appropriate trace level
Sergunb 0:8918a71cdbe9 37 #define TRACE_LEVEL CRYPTO_TRACE_LEVEL
Sergunb 0:8918a71cdbe9 38
Sergunb 0:8918a71cdbe9 39 //Dependencies
Sergunb 0:8918a71cdbe9 40 #include <string.h>
Sergunb 0:8918a71cdbe9 41 #include "crypto.h"
Sergunb 0:8918a71cdbe9 42 #include "cipher_mode_cbc.h"
Sergunb 0:8918a71cdbe9 43 #include "debug.h"
Sergunb 0:8918a71cdbe9 44
Sergunb 0:8918a71cdbe9 45 //Check crypto library configuration
Sergunb 0:8918a71cdbe9 46 #if (CBC_SUPPORT == ENABLED)
Sergunb 0:8918a71cdbe9 47
Sergunb 0:8918a71cdbe9 48
Sergunb 0:8918a71cdbe9 49 /**
Sergunb 0:8918a71cdbe9 50 * @brief CBC encryption
Sergunb 0:8918a71cdbe9 51 * @param[in] cipher Cipher algorithm
Sergunb 0:8918a71cdbe9 52 * @param[in] context Cipher algorithm context
Sergunb 0:8918a71cdbe9 53 * @param[in,out] iv Initialization vector
Sergunb 0:8918a71cdbe9 54 * @param[in] p Plaintext to be encrypted
Sergunb 0:8918a71cdbe9 55 * @param[out] c Ciphertext resulting from the encryption
Sergunb 0:8918a71cdbe9 56 * @param[in] length Total number of data bytes to be encrypted
Sergunb 0:8918a71cdbe9 57 * @return Error code
Sergunb 0:8918a71cdbe9 58 **/
Sergunb 0:8918a71cdbe9 59
Sergunb 0:8918a71cdbe9 60 error_t cbcEncrypt(const CipherAlgo *cipher, void *context,
Sergunb 0:8918a71cdbe9 61 uint8_t *iv, const uint8_t *p, uint8_t *c, size_t length)
Sergunb 0:8918a71cdbe9 62 {
Sergunb 0:8918a71cdbe9 63 size_t i;
Sergunb 0:8918a71cdbe9 64
Sergunb 0:8918a71cdbe9 65 //CBC mode operates in a block-by-block fashion
Sergunb 0:8918a71cdbe9 66 while(length >= cipher->blockSize)
Sergunb 0:8918a71cdbe9 67 {
Sergunb 0:8918a71cdbe9 68 //XOR input block with IV contents
Sergunb 0:8918a71cdbe9 69 for(i = 0; i < cipher->blockSize; i++)
Sergunb 0:8918a71cdbe9 70 c[i] = p[i] ^ iv[i];
Sergunb 0:8918a71cdbe9 71
Sergunb 0:8918a71cdbe9 72 //Encrypt the current block based upon the output
Sergunb 0:8918a71cdbe9 73 //of the previous encryption
Sergunb 0:8918a71cdbe9 74 cipher->encryptBlock(context, c, c);
Sergunb 0:8918a71cdbe9 75
Sergunb 0:8918a71cdbe9 76 //Update IV with output block contents
Sergunb 0:8918a71cdbe9 77 memcpy(iv, c, cipher->blockSize);
Sergunb 0:8918a71cdbe9 78
Sergunb 0:8918a71cdbe9 79 //Next block
Sergunb 0:8918a71cdbe9 80 p += cipher->blockSize;
Sergunb 0:8918a71cdbe9 81 c += cipher->blockSize;
Sergunb 0:8918a71cdbe9 82 length -= cipher->blockSize;
Sergunb 0:8918a71cdbe9 83 }
Sergunb 0:8918a71cdbe9 84
Sergunb 0:8918a71cdbe9 85 //The plaintext must be a multiple of the block size
Sergunb 0:8918a71cdbe9 86 if(length != 0)
Sergunb 0:8918a71cdbe9 87 return ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 88
Sergunb 0:8918a71cdbe9 89 //Successful encryption
Sergunb 0:8918a71cdbe9 90 return NO_ERROR;
Sergunb 0:8918a71cdbe9 91 }
Sergunb 0:8918a71cdbe9 92
Sergunb 0:8918a71cdbe9 93
Sergunb 0:8918a71cdbe9 94 /**
Sergunb 0:8918a71cdbe9 95 * @brief CBC decryption
Sergunb 0:8918a71cdbe9 96 * @param[in] cipher Cipher algorithm
Sergunb 0:8918a71cdbe9 97 * @param[in] context Cipher algorithm context
Sergunb 0:8918a71cdbe9 98 * @param[in,out] iv Initialization vector
Sergunb 0:8918a71cdbe9 99 * @param[in] c Ciphertext to be decrypted
Sergunb 0:8918a71cdbe9 100 * @param[out] p Plaintext resulting from the decryption
Sergunb 0:8918a71cdbe9 101 * @param[in] length Total number of data bytes to be decrypted
Sergunb 0:8918a71cdbe9 102 * @return Error code
Sergunb 0:8918a71cdbe9 103 **/
Sergunb 0:8918a71cdbe9 104
Sergunb 0:8918a71cdbe9 105 error_t cbcDecrypt(const CipherAlgo *cipher, void *context,
Sergunb 0:8918a71cdbe9 106 uint8_t *iv, const uint8_t *c, uint8_t *p, size_t length)
Sergunb 0:8918a71cdbe9 107 {
Sergunb 0:8918a71cdbe9 108 size_t i;
Sergunb 0:8918a71cdbe9 109 uint8_t t[16];
Sergunb 0:8918a71cdbe9 110
Sergunb 0:8918a71cdbe9 111 //CBC mode operates in a block-by-block fashion
Sergunb 0:8918a71cdbe9 112 while(length >= cipher->blockSize)
Sergunb 0:8918a71cdbe9 113 {
Sergunb 0:8918a71cdbe9 114 //Save input block
Sergunb 0:8918a71cdbe9 115 memcpy(t, c, cipher->blockSize);
Sergunb 0:8918a71cdbe9 116
Sergunb 0:8918a71cdbe9 117 //Decrypt the current block
Sergunb 0:8918a71cdbe9 118 cipher->decryptBlock(context, c, p);
Sergunb 0:8918a71cdbe9 119
Sergunb 0:8918a71cdbe9 120 //XOR output block with IV contents
Sergunb 0:8918a71cdbe9 121 for(i = 0; i < cipher->blockSize; i++)
Sergunb 0:8918a71cdbe9 122 p[i] ^= iv[i];
Sergunb 0:8918a71cdbe9 123
Sergunb 0:8918a71cdbe9 124 //Update IV with input block contents
Sergunb 0:8918a71cdbe9 125 memcpy(iv, t, cipher->blockSize);
Sergunb 0:8918a71cdbe9 126
Sergunb 0:8918a71cdbe9 127 //Next block
Sergunb 0:8918a71cdbe9 128 c += cipher->blockSize;
Sergunb 0:8918a71cdbe9 129 p += cipher->blockSize;
Sergunb 0:8918a71cdbe9 130 length -= cipher->blockSize;
Sergunb 0:8918a71cdbe9 131 }
Sergunb 0:8918a71cdbe9 132
Sergunb 0:8918a71cdbe9 133 //The ciphertext must be a multiple of the block size
Sergunb 0:8918a71cdbe9 134 if(length != 0)
Sergunb 0:8918a71cdbe9 135 return ERROR_INVALID_LENGTH;
Sergunb 0:8918a71cdbe9 136
Sergunb 0:8918a71cdbe9 137 //Successful encryption
Sergunb 0:8918a71cdbe9 138 return NO_ERROR;
Sergunb 0:8918a71cdbe9 139 }
Sergunb 0:8918a71cdbe9 140
Sergunb 0:8918a71cdbe9 141 #endif
Sergunb 0:8918a71cdbe9 142