cmac.cpp

00001 /**************************************************************************
00002 Copyright (C) 2009 Lander Casado, Philippas Tsigas
00003 All rights reserved.
00004 Permission is hereby granted, free of charge, to any person obtaining
00005 a copy of this software and associated documentation files 
00006 (the "Software"), to deal with the Software without restriction, including
00007 without limitation the rights to use, copy, modify, merge, publish, 
00008 distribute, sublicense, and/or sell copies of the Software, and to
00009 permit persons to whom the Software is furnished to do so, subject to
00010 the following conditions: 
00011 Redistributions of source code must retain the above copyright notice, 
00012 this list of conditions and the following disclaimers. Redistributions in
00013 binary form must reproduce the above copyright notice, this list of
00014 conditions and the following disclaimers in the documentation and/or 
00015 other materials provided with the distribution.
00016 In no event shall the authors or copyright holders be liable for any special,
00017 incidental, indirect or consequential damages of any kind, or any damages 
00018 whatsoever resulting from loss of use, data or profits, whether or not 
00019 advised of the possibility of damage, and on any theory of liability, 
00020 arising out of or in connection with the use or performance of this software.
00021  
00022 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
00023 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00024 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00025 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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00027 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
00028 DEALINGS WITH THE SOFTWARE
00029 *****************************************************************************/
00030 //#include <sys/param.h>
00031 //#include <sys/systm.h> 
00032 #include <stdint.h>
00033 #include "aes.h"
00034 #include "cmac.h"
00035 #include "utilities.h"
00036 
00037 #define LSHIFT(v, r) do {                                       \
00038   int32_t i;                                                  \
00039            for (i = 0; i < 15; i++)                                \
00040                     (r)[i] = (v)[i] << 1 | (v)[i + 1] >> 7;         \
00041             (r)[15] = (v)[15] << 1;                                 \
00042     } while (0)
00043     
00044 #define XOR(v, r) do {                                          \
00045             int32_t i;                                                  \
00046             for (i = 0; i < 16; i++)     \
00047         {   \
00048                     (r)[i] = (r)[i] ^ (v)[i]; \
00049         }                          \
00050     } while (0) \
00051 
00052 
00053 void AES_CMAC_Init(AES_CMAC_CTX *ctx)
00054 {
00055             memset1(ctx->X, 0, sizeof ctx->X);
00056             ctx->M_n = 0;
00057         memset1(ctx->rijndael.ksch, '\0', 240);
00058 }
00059     
00060 void AES_CMAC_SetKey(AES_CMAC_CTX *ctx, const uint8_t key[AES_CMAC_KEY_LENGTH])
00061 {
00062            //rijndael_set_key_enc_only(&ctx->rijndael, key, 128);
00063        aes_set_key( key, AES_CMAC_KEY_LENGTH, &ctx->rijndael);
00064 }
00065     
00066 void AES_CMAC_Update(AES_CMAC_CTX *ctx, const uint8_t *data, uint32_t len)
00067 {
00068             uint32_t mlen;
00069         uint8_t in[16];
00070     
00071             if (ctx->M_n > 0) {
00072                   mlen = MIN(16 - ctx->M_n, len);
00073                     memcpy1(ctx->M_last + ctx->M_n, data, mlen);
00074                     ctx->M_n += mlen;
00075                     if (ctx->M_n < 16 || len == mlen)
00076                             return;
00077                    XOR(ctx->M_last, ctx->X);
00078                     //rijndael_encrypt(&ctx->rijndael, ctx->X, ctx->X);
00079             aes_encrypt( ctx->X, ctx->X, &ctx->rijndael);
00080                     data += mlen;
00081                     len -= mlen;
00082             }
00083             while (len > 16) {      /* not last block */
00084          
00085                     XOR(data, ctx->X);
00086                     //rijndael_encrypt(&ctx->rijndael, ctx->X, ctx->X);
00087 
00088                     memcpy1(in, &ctx->X[0], 16); //Bestela ez du ondo iten
00089             aes_encrypt( in, in, &ctx->rijndael);
00090                     memcpy1(&ctx->X[0], in, 16);
00091 
00092                     data += 16;
00093                     len -= 16;
00094             }
00095             /* potential last block, save it */
00096             memcpy1(ctx->M_last, data, len);
00097             ctx->M_n = len;
00098 }
00099    
00100 void AES_CMAC_Final(uint8_t digest[AES_CMAC_DIGEST_LENGTH], AES_CMAC_CTX *ctx)
00101 {
00102             uint8_t K[16];
00103         uint8_t in[16];
00104             /* generate subkey K1 */
00105             memset1(K, '\0', 16);
00106 
00107             //rijndael_encrypt(&ctx->rijndael, K, K);
00108 
00109             aes_encrypt( K, K, &ctx->rijndael);
00110 
00111             if (K[0] & 0x80) {
00112                     LSHIFT(K, K);
00113                    K[15] ^= 0x87;
00114             } else
00115                     LSHIFT(K, K);
00116 
00117        
00118             if (ctx->M_n == 16) {
00119                     /* last block was a complete block */
00120                     XOR(K, ctx->M_last);
00121 
00122            } else {
00123                    /* generate subkey K2 */
00124                   if (K[0] & 0x80) {
00125                           LSHIFT(K, K);
00126                           K[15] ^= 0x87;
00127                   } else
00128                            LSHIFT(K, K);
00129 
00130                    /* padding(M_last) */
00131                    ctx->M_last[ctx->M_n] = 0x80;
00132                    while (++ctx->M_n < 16)
00133                          ctx->M_last[ctx->M_n] = 0;
00134    
00135                   XOR(K, ctx->M_last);
00136           
00137            
00138            }
00139            XOR(ctx->M_last, ctx->X);
00140       
00141            //rijndael_encrypt(&ctx->rijndael, ctx->X, digest);
00142     
00143        memcpy1(in, &ctx->X[0], 16); //Bestela ez du ondo iten
00144        aes_encrypt(in, digest, &ctx->rijndael);
00145            memset1(K, 0, sizeof K);
00146 
00147 }