1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis 2 * 3 * LibTomCrypt is a library that provides various cryptographic 4 * algorithms in a highly modular and flexible manner. 5 * 6 * The library is free for all purposes without any express 7 * guarantee it works. 8 * 9 * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com 10 */ 11 #include "tomcrypt.h" 12 13 /** 14 @file xcbc_process.c 15 XCBC Support, process blocks with XCBC 16 */ 17 18 #ifdef LTC_XCBC 19 20 /** Process data through XCBC-MAC 21 @param xcbc The XCBC-MAC state 22 @param in Input data to process 23 @param inlen Length of input in octets 24 Return CRYPT_OK on success 25 */ 26 int xcbc_process(xcbc_state *xcbc, const unsigned char *in, unsigned long inlen) 27 { 28 int err; 29 #ifdef LTC_FAST 30 int x; 31 #endif 32 33 LTC_ARGCHK(xcbc != NULL); 34 LTC_ARGCHK(in != NULL); 35 36 /* check structure */ 37 if ((err = cipher_is_valid(xcbc->cipher)) != CRYPT_OK) { 38 return err; 39 } 40 41 if ((xcbc->blocksize > cipher_descriptor[xcbc->cipher].block_length) || (xcbc->blocksize < 0) || 42 (xcbc->buflen > xcbc->blocksize) || (xcbc->buflen < 0)) { 43 return CRYPT_INVALID_ARG; 44 } 45 46 #ifdef LTC_FAST 47 if (xcbc->buflen == 0) { 48 while (inlen > (unsigned long)xcbc->blocksize) { 49 for (x = 0; x < xcbc->blocksize; x += sizeof(LTC_FAST_TYPE)) { 50 *((LTC_FAST_TYPE*)&(xcbc->IV[x])) ^= *((LTC_FAST_TYPE*)&(in[x])); 51 } 52 cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key); 53 in += xcbc->blocksize; 54 inlen -= xcbc->blocksize; 55 } 56 } 57 #endif 58 59 while (inlen) { 60 if (xcbc->buflen == xcbc->blocksize) { 61 cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key); 62 xcbc->buflen = 0; 63 } 64 xcbc->IV[xcbc->buflen++] ^= *in++; 65 --inlen; 66 } 67 return CRYPT_OK; 68 } 69 70 #endif 71 72 /* $Source: /cvs/libtom/libtomcrypt/src/mac/xcbc/xcbc_process.c,v $ */ 73 /* $Revision: 1.9 $ */ 74 /* $Date: 2006/11/09 22:43:52 $ */ 75 76
