annotate omac_process.c @ 17:1a066933c5e1 libtomcrypt

Removed PDFs, if people want them there's the .tex
author Matt Johnston <matt@ucc.asn.au>
date Tue, 15 Jun 2004 14:32:29 +0000
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children 5d99163f7e32
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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
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2 *
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3 * LibTomCrypt is a library that provides various cryptographic
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4 * algorithms in a highly modular and flexible manner.
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5 *
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6 * The library is free for all purposes without any express
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7 * guarantee it works.
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8 *
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9 * Tom St Denis, [email protected], http://libtomcrypt.org
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10 */
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11 /* OMAC1 Support by Tom St Denis (for 64 and 128 bit block ciphers only) */
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12 #include "mycrypt.h"
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13
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14 #ifdef OMAC
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15
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16 int omac_process(omac_state *state, const unsigned char *buf, unsigned long len)
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17 {
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18 int err, n, x;
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19
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20 _ARGCHK(state != NULL);
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21 _ARGCHK(buf != NULL);
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22 if ((err = cipher_is_valid(state->cipher_idx)) != CRYPT_OK) {
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23 return err;
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24 }
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25
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26 if ((state->buflen > (int)sizeof(state->block)) || (state->buflen < 0) ||
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27 (state->blklen > (int)sizeof(state->block)) || (state->buflen > state->blklen)) {
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28 return CRYPT_INVALID_ARG;
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29 }
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30
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31 while (len != 0) {
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32 /* ok if the block is full we xor in prev, encrypt and replace prev */
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33 if (state->buflen == state->blklen) {
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34 for (x = 0; x < state->blklen; x++) {
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35 state->block[x] ^= state->prev[x];
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36 }
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37 cipher_descriptor[state->cipher_idx].ecb_encrypt(state->block, state->prev, &state->key);
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38 state->buflen = 0;
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39 }
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40
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41 /* add bytes */
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42 n = MIN(len, (unsigned long)(state->blklen - state->buflen));
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43 memcpy(state->block + state->buflen, buf, n);
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44 state->buflen += n;
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45 len -= n;
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46 buf += n;
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47 }
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48
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49 return CRYPT_OK;
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50 }
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51
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52 #endif
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53