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cyclone_crypto/des3.c@0:8918a71cdbe9, 2017-02-04 (annotated)

Committer:
Sergunb
Date:
Sat Feb 04 18:15:49 2017 +0000
Revision:
0:8918a71cdbe9
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Sergunb 0:8918a71cdbe9 1 /**
Sergunb 0:8918a71cdbe9 2 * @file des3.c
Sergunb 0:8918a71cdbe9 3 * @brief Triple DES (Triple Data Encryption Algorithm)
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 * Triple DES is an encryption algorithm designed to encipher and decipher blocks
Sergunb 0:8918a71cdbe9 28 * of 64 bits under control of a 192-bit key. Refer to FIPS 46-3 for more details
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 <string.h>
Sergunb 0:8918a71cdbe9 39 #include "crypto.h"
Sergunb 0:8918a71cdbe9 40 #include "des3.h"
Sergunb 0:8918a71cdbe9 41 #include "des.h"
Sergunb 0:8918a71cdbe9 42
Sergunb 0:8918a71cdbe9 43 //Check crypto library configuration
Sergunb 0:8918a71cdbe9 44 #if (DES3_SUPPORT == ENABLED)
Sergunb 0:8918a71cdbe9 45
Sergunb 0:8918a71cdbe9 46 //Common interface for encryption algorithms
Sergunb 0:8918a71cdbe9 47 const CipherAlgo des3CipherAlgo =
Sergunb 0:8918a71cdbe9 48 {
Sergunb 0:8918a71cdbe9 49 "3DES",
Sergunb 0:8918a71cdbe9 50 sizeof(Des3Context),
Sergunb 0:8918a71cdbe9 51 CIPHER_ALGO_TYPE_BLOCK,
Sergunb 0:8918a71cdbe9 52 DES3_BLOCK_SIZE,
Sergunb 0:8918a71cdbe9 53 (CipherAlgoInit) des3Init,
Sergunb 0:8918a71cdbe9 54 NULL,
Sergunb 0:8918a71cdbe9 55 NULL,
Sergunb 0:8918a71cdbe9 56 (CipherAlgoEncryptBlock) des3EncryptBlock,
Sergunb 0:8918a71cdbe9 57 (CipherAlgoDecryptBlock) des3DecryptBlock
Sergunb 0:8918a71cdbe9 58 };
Sergunb 0:8918a71cdbe9 59
Sergunb 0:8918a71cdbe9 60
Sergunb 0:8918a71cdbe9 61 /**
Sergunb 0:8918a71cdbe9 62 * @brief Initialize a Triple DES context using the supplied key
Sergunb 0:8918a71cdbe9 63 * @param[in] context Pointer to the Triple DES context to initialize
Sergunb 0:8918a71cdbe9 64 * @param[in] key Pointer to the key
Sergunb 0:8918a71cdbe9 65 * @param[in] keyLength Length of the key
Sergunb 0:8918a71cdbe9 66 * @return Error code
Sergunb 0:8918a71cdbe9 67 **/
Sergunb 0:8918a71cdbe9 68
Sergunb 0:8918a71cdbe9 69 error_t des3Init(Des3Context *context, const uint8_t *key, size_t keyLength)
Sergunb 0:8918a71cdbe9 70 {
Sergunb 0:8918a71cdbe9 71 //Check key length
Sergunb 0:8918a71cdbe9 72 if(keyLength == 8)
Sergunb 0:8918a71cdbe9 73 {
Sergunb 0:8918a71cdbe9 74 //This option provides backward compatibility with DES, because the
Sergunb 0:8918a71cdbe9 75 //first and second DES operations cancel out
Sergunb 0:8918a71cdbe9 76 desInit(&context->k1, key, 8);
Sergunb 0:8918a71cdbe9 77 desInit(&context->k2, key, 8);
Sergunb 0:8918a71cdbe9 78 desInit(&context->k3, key, 8);
Sergunb 0:8918a71cdbe9 79 }
Sergunb 0:8918a71cdbe9 80 else if(keyLength == 16)
Sergunb 0:8918a71cdbe9 81 {
Sergunb 0:8918a71cdbe9 82 //If the key length is 128 bits including parity, the first 8 bytes of the
Sergunb 0:8918a71cdbe9 83 //encoding represent the key used for the two outer DES operations, and
Sergunb 0:8918a71cdbe9 84 //the second 8 bytes represent the key used for the inner DES operation
Sergunb 0:8918a71cdbe9 85 desInit(&context->k1, key, 8);
Sergunb 0:8918a71cdbe9 86 desInit(&context->k2, key + 8, 8);
Sergunb 0:8918a71cdbe9 87 desInit(&context->k3, key, 8);
Sergunb 0:8918a71cdbe9 88 }
Sergunb 0:8918a71cdbe9 89 else if(keyLength == 24)
Sergunb 0:8918a71cdbe9 90 {
Sergunb 0:8918a71cdbe9 91 //If the key length is 192 bits including parity, then three independent DES
Sergunb 0:8918a71cdbe9 92 //keys are represented, in the order in which they are used for encryption
Sergunb 0:8918a71cdbe9 93 desInit(&context->k1, key, 8);
Sergunb 0:8918a71cdbe9 94 desInit(&context->k2, key + 8, 8);
Sergunb 0:8918a71cdbe9 95 desInit(&context->k3, key + 16, 8);
Sergunb 0:8918a71cdbe9 96 }
Sergunb 0:8918a71cdbe9 97 else
Sergunb 0:8918a71cdbe9 98 {
Sergunb 0:8918a71cdbe9 99 //Invalid key length...
Sergunb 0:8918a71cdbe9 100 return ERROR_INVALID_KEY_LENGTH;
Sergunb 0:8918a71cdbe9 101 }
Sergunb 0:8918a71cdbe9 102
Sergunb 0:8918a71cdbe9 103 //No error to report
Sergunb 0:8918a71cdbe9 104 return NO_ERROR;
Sergunb 0:8918a71cdbe9 105 }
Sergunb 0:8918a71cdbe9 106
Sergunb 0:8918a71cdbe9 107
Sergunb 0:8918a71cdbe9 108 /**
Sergunb 0:8918a71cdbe9 109 * @brief Encrypt a 8-byte block using Triple DES algorithm
Sergunb 0:8918a71cdbe9 110 * @param[in] context Pointer to the Triple DES context
Sergunb 0:8918a71cdbe9 111 * @param[in] input Plaintext block to encrypt
Sergunb 0:8918a71cdbe9 112 * @param[out] output Ciphertext block resulting from encryption
Sergunb 0:8918a71cdbe9 113 **/
Sergunb 0:8918a71cdbe9 114
Sergunb 0:8918a71cdbe9 115 void des3EncryptBlock(Des3Context *context, const uint8_t *input, uint8_t *output)
Sergunb 0:8918a71cdbe9 116 {
Sergunb 0:8918a71cdbe9 117 //The first pass is a DES encryption
Sergunb 0:8918a71cdbe9 118 desEncryptBlock(&context->k1, input, output);
Sergunb 0:8918a71cdbe9 119 //The second pass is a DES decryption of the first ciphertext result
Sergunb 0:8918a71cdbe9 120 desDecryptBlock(&context->k2, output, output);
Sergunb 0:8918a71cdbe9 121 //The third pass is a DES encryption of the second pass result
Sergunb 0:8918a71cdbe9 122 desEncryptBlock(&context->k3, output, output);
Sergunb 0:8918a71cdbe9 123 }
Sergunb 0:8918a71cdbe9 124
Sergunb 0:8918a71cdbe9 125
Sergunb 0:8918a71cdbe9 126 /**
Sergunb 0:8918a71cdbe9 127 * @brief Decrypt a 8-byte block using Triple DES algorithm
Sergunb 0:8918a71cdbe9 128 * @param[in] context Pointer to the Triple DES context
Sergunb 0:8918a71cdbe9 129 * @param[in] input Ciphertext block to decrypt
Sergunb 0:8918a71cdbe9 130 * @param[out] output Plaintext block resulting from decryption
Sergunb 0:8918a71cdbe9 131 **/
Sergunb 0:8918a71cdbe9 132
Sergunb 0:8918a71cdbe9 133 void des3DecryptBlock(Des3Context *context, const uint8_t *input, uint8_t *output)
Sergunb 0:8918a71cdbe9 134 {
Sergunb 0:8918a71cdbe9 135 //The first pass is a DES decryption
Sergunb 0:8918a71cdbe9 136 desDecryptBlock(&context->k3, input, output);
Sergunb 0:8918a71cdbe9 137 //The second pass is a DES encryption of the first pass result
Sergunb 0:8918a71cdbe9 138 desEncryptBlock(&context->k2, output, output);
Sergunb 0:8918a71cdbe9 139 //The third pass is a DES decryption of the second ciphertext result
Sergunb 0:8918a71cdbe9 140 desDecryptBlock(&context->k1, output, output);
Sergunb 0:8918a71cdbe9 141 }
Sergunb 0:8918a71cdbe9 142
Sergunb 0:8918a71cdbe9 143 #endif
Sergunb 0:8918a71cdbe9 144