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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 /* EAX Implementation by Tom St Denis */ |
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13 #include "mycrypt.h" |
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14 |
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15 #ifdef EAX_MODE |
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16 |
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17 int eax_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, unsigned long noncelen, |
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20 const unsigned char *header, unsigned long headerlen, |
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21 const unsigned char *ct, unsigned long ctlen, |
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22 unsigned char *pt, |
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23 unsigned char *tag, unsigned long taglen, |
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24 int *res) |
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25 { |
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143
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26 int err; |
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27 eax_state *eax; |
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28 unsigned char *buf; |
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29 unsigned long buflen; |
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30 |
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31 _ARGCHK(res != NULL); |
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32 |
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33 /* default to zero */ |
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34 *res = 0; |
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35 |
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143
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36 /* allocate ram */ |
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37 buf = XMALLOC(taglen); |
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38 eax = XMALLOC(sizeof(eax_state)); |
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39 if (eax == NULL || buf == NULL) { |
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40 if (eax != NULL) { |
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41 XFREE(eax); |
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42 } |
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43 if (buf != NULL) { |
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44 XFREE(buf); |
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45 } |
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46 return CRYPT_MEM; |
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47 } |
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48 |
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143
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49 if ((err = eax_init(eax, cipher, key, keylen, nonce, noncelen, header, headerlen)) != CRYPT_OK) { |
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50 goto __ERR; |
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51 } |
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52 |
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53 if ((err = eax_decrypt(eax, ct, pt, ctlen)) != CRYPT_OK) { |
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54 goto __ERR; |
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55 } |
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56 |
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143
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57 buflen = taglen; |
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58 if ((err = eax_done(eax, buf, &buflen)) != CRYPT_OK) { |
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59 goto __ERR; |
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60 } |
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61 |
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62 /* compare tags */ |
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63 if (buflen >= taglen && memcmp(buf, tag, taglen) == 0) { |
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64 *res = 1; |
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65 } |
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143
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66 |
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67 err = CRYPT_OK; |
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68 __ERR: |
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69 #ifdef CLEAN_STACK |
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143
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70 zeromem(buf, taglen); |
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71 zeromem(eax, sizeof(eax_state)); |
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72 #endif |
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143
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73 |
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74 XFREE(eax); |
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75 XFREE(buf); |
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76 |
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77 return err; |
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78 } |
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79 |
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80 #endif |
