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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 |
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12 /* OCB Implementation by Tom St Denis */ |
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13 #include "mycrypt.h" |
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14 |
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15 #ifdef OCB_MODE |
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16 |
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17 int ocb_decrypt_verify_memory(int cipher, |
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18 const unsigned char *key, unsigned long keylen, |
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19 const unsigned char *nonce, |
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20 const unsigned char *ct, unsigned long ctlen, |
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21 unsigned char *pt, |
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22 const unsigned char *tag, unsigned long taglen, |
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23 int *res) |
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24 { |
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25 int err; |
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143
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26 ocb_state *ocb; |
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27 |
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28 _ARGCHK(key != NULL); |
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29 _ARGCHK(nonce != NULL); |
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30 _ARGCHK(pt != NULL); |
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31 _ARGCHK(ct != NULL); |
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32 _ARGCHK(tag != NULL); |
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33 _ARGCHK(res != NULL); |
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34 |
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143
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35 /* allocate memory */ |
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36 ocb = XMALLOC(sizeof(ocb_state)); |
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37 if (ocb == NULL) { |
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38 return CRYPT_MEM; |
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39 } |
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40 |
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41 if ((err = ocb_init(ocb, cipher, key, keylen, nonce)) != CRYPT_OK) { |
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42 goto __ERR; |
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43 } |
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44 |
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143
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45 while (ctlen > (unsigned long)ocb->block_len) { |
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46 if ((err = ocb_decrypt(ocb, ct, pt)) != CRYPT_OK) { |
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47 goto __ERR; |
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48 } |
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143
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49 ctlen -= ocb->block_len; |
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50 pt += ocb->block_len; |
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51 ct += ocb->block_len; |
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52 } |
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53 |
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143
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54 err = ocb_done_decrypt(ocb, ct, ctlen, pt, tag, taglen, res); |
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55 __ERR: |
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56 #ifdef CLEAN_STACK |
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57 zeromem(ocb, sizeof(ocb_state)); |
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58 #endif |
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59 |
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60 XFREE(ocb); |
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61 |
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62 return err; |
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63 } |
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64 |
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65 #endif |
