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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.com |
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10 */ |
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11 |
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12 /* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b |
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13 * |
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14 * All curves taken from NIST recommendation paper of July 1999 |
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15 * Available at http://csrc.nist.gov/cryptval/dss.htm |
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16 */ |
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17 #include "tomcrypt.h" |
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18 |
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19 /** |
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20 @file ecc_ansi_x963_import.c |
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21 ECC Crypto, Tom St Denis |
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22 */ |
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23 |
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24 #ifdef MECC |
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25 |
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26 /** Import an ANSI X9.63 format public key |
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27 @param in The input data to read |
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28 @param inlen The length of the input data |
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29 @param key [out] destination to store imported key \ |
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30 */ |
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31 int ecc_ansi_x963_import(const unsigned char *in, unsigned long inlen, ecc_key *key) |
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32 { |
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33 return ecc_ansi_x963_import_ex(in, inlen, key, NULL); |
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34 } |
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35 |
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36 int ecc_ansi_x963_import_ex(const unsigned char *in, unsigned long inlen, ecc_key *key, ltc_ecc_set_type *dp) |
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37 { |
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38 int x, err; |
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39 |
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40 LTC_ARGCHK(in != NULL); |
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41 LTC_ARGCHK(key != NULL); |
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42 |
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43 /* must be odd */ |
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44 if ((inlen & 1) == 0) { |
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45 return CRYPT_INVALID_ARG; |
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46 } |
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47 |
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48 /* init key */ |
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49 if (mp_init_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, NULL) != CRYPT_OK) { |
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50 return CRYPT_MEM; |
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51 } |
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52 |
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53 /* check for 4, 6 or 7 */ |
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54 if (in[0] != 4 && in[0] != 6 && in[0] != 7) { |
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55 err = CRYPT_INVALID_PACKET; |
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56 goto error; |
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57 } |
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58 |
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59 /* read data */ |
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60 if ((err = mp_read_unsigned_bin(key->pubkey.x, (unsigned char *)in+1, (inlen-1)>>1)) != CRYPT_OK) { |
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61 goto error; |
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62 } |
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63 |
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64 if ((err = mp_read_unsigned_bin(key->pubkey.y, (unsigned char *)in+1+((inlen-1)>>1), (inlen-1)>>1)) != CRYPT_OK) { |
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65 goto error; |
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66 } |
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67 if ((err = mp_set(key->pubkey.z, 1)) != CRYPT_OK) { goto error; } |
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68 |
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69 if (dp == NULL) { |
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70 /* determine the idx */ |
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71 for (x = 0; ltc_ecc_sets[x].size != 0; x++) { |
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72 if ((unsigned)ltc_ecc_sets[x].size >= ((inlen-1)>>1)) { |
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73 break; |
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74 } |
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75 } |
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76 if (ltc_ecc_sets[x].size == 0) { |
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77 err = CRYPT_INVALID_PACKET; |
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78 goto error; |
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79 } |
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80 /* set the idx */ |
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81 key->idx = x; |
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82 key->dp = <c_ecc_sets[x]; |
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83 } else { |
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84 if (((inlen-1)>>1) != (unsigned long) dp->size) { |
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85 err = CRYPT_INVALID_PACKET; |
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86 goto error; |
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87 } |
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88 key->idx = -1; |
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89 key->dp = dp; |
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90 } |
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91 key->type = PK_PUBLIC; |
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92 |
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93 /* we're done */ |
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94 return CRYPT_OK; |
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95 error: |
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96 mp_clear_multi(key->pubkey.x, key->pubkey.y, key->pubkey.z, key->k, NULL); |
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97 return err; |
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98 } |
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99 |
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100 #endif |
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101 |
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102 /* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_ansi_x963_import.c,v $ */ |
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103 /* $Revision: 1.9 $ */ |
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104 /* $Date: 2006/12/04 22:17:46 $ */ |
