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      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 pmac_process.c
     15    PMAC implementation, process data, by Tom St Denis
     16 */
     17 
     18 
     19 #ifdef LTC_PMAC
     20 
     21 /**
     22   Process data in a PMAC stream
     23   @param pmac     The PMAC state
     24   @param in       The data to send through PMAC
     25   @param inlen    The length of the data to send through PMAC
     26   @return CRYPT_OK if successful
     27 */
     28 int pmac_process(pmac_state *pmac, const unsigned char *in, unsigned long inlen)
     29 {
     30    int err, n;
     31    unsigned long x;
     32    unsigned char Z[MAXBLOCKSIZE];
     33 
     34    LTC_ARGCHK(pmac != NULL);
     35    LTC_ARGCHK(in   != NULL);
     36    if ((err = cipher_is_valid(pmac->cipher_idx)) != CRYPT_OK) {
     37       return err;
     38    }
     39 
     40    if ((pmac->buflen > (int)sizeof(pmac->block)) || (pmac->buflen < 0) ||
     41        (pmac->block_len > (int)sizeof(pmac->block)) || (pmac->buflen > pmac->block_len)) {
     42       return CRYPT_INVALID_ARG;
     43    }
     44 
     45 #ifdef LTC_FAST
     46    if (pmac->buflen == 0 && inlen > 16) {
     47       unsigned long y;
     48       for (x = 0; x < (inlen - 16); x += 16) {
     49           pmac_shift_xor(pmac);
     50           for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
     51               *((LTC_FAST_TYPE*)(&Z[y])) = *((LTC_FAST_TYPE*)(&in[y])) ^ *((LTC_FAST_TYPE*)(&pmac->Li[y]));
     52           }
     53           if ((err = cipher_descriptor[pmac->cipher_idx].ecb_encrypt(Z, Z, &pmac->key)) != CRYPT_OK) {
     54              return err;
     55           }
     56           for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
     57               *((LTC_FAST_TYPE*)(&pmac->checksum[y])) ^= *((LTC_FAST_TYPE*)(&Z[y]));
     58           }
     59           in += 16;
     60       }
     61       inlen -= x;
     62    }
     63 #endif
     64 
     65    while (inlen != 0) {
     66        /* ok if the block is full we xor in prev, encrypt and replace prev */
     67        if (pmac->buflen == pmac->block_len) {
     68           pmac_shift_xor(pmac);
     69           for (x = 0; x < (unsigned long)pmac->block_len; x++) {
     70                Z[x] = pmac->Li[x] ^ pmac->block[x];
     71           }
     72           if ((err = cipher_descriptor[pmac->cipher_idx].ecb_encrypt(Z, Z, &pmac->key)) != CRYPT_OK) {
     73              return err;
     74            }
     75           for (x = 0; x < (unsigned long)pmac->block_len; x++) {
     76               pmac->checksum[x] ^= Z[x];
     77           }
     78           pmac->buflen = 0;
     79        }
     80 
     81        /* add bytes */
     82        n = MIN(inlen, (unsigned long)(pmac->block_len - pmac->buflen));
     83        XMEMCPY(pmac->block + pmac->buflen, in, n);
     84        pmac->buflen  += n;
     85        inlen         -= n;
     86        in            += n;
     87    }
     88 
     89 #ifdef LTC_CLEAN_STACK
     90    zeromem(Z, sizeof(Z));
     91 #endif
     92 
     93    return CRYPT_OK;
     94 }
     95 
     96 #endif
     97 
     98 /* $Source: /cvs/libtom/libtomcrypt/src/mac/pmac/pmac_process.c,v $ */
     99 /* $Revision: 1.8 $ */
    100 /* $Date: 2006/11/03 00:39:49 $ */
    101