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comparison pkcs_1_pss_decode.c @ 15:6362d3854bb4 libtomcrypt-orig

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0.96 release of LibTomCrypt
author Matt Johnston <matt@ucc.asn.au>
date Tue, 15 Jun 2004 14:07:21 +0000
parents 7faae8f46238
children 5d99163f7e32
comparison
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3:7faae8f46238 15:6362d3854bb4
58 for (y = 0; y < hLen; y++) { 58 for (y = 0; y < hLen; y++) {
59 hash[y] = sig[x++]; 59 hash[y] = sig[x++];
60 } 60 }
61 61
62 /* check the MSB */ 62 /* check the MSB */
63 if ((sig[0] & ~(0xFF >> ((modulus_len<<3) - modulus_bitlen))) != 0) { 63 if ((sig[0] & ~(0xFF >> ((modulus_len<<3) - (modulus_bitlen-1)))) != 0) {
64 return CRYPT_OK; 64 return CRYPT_OK;
65 } 65 }
66 66
67 /* generate mask of length modulus_len - hLen - 1 from hash */ 67 /* generate mask of length modulus_len - hLen - 1 from hash */
68 if ((err = pkcs_1_mgf1(hash, hLen, hash_idx, mask, modulus_len - hLen - 1)) != CRYPT_OK) { 68 if ((err = pkcs_1_mgf1(hash, hLen, hash_idx, mask, modulus_len - hLen - 1)) != CRYPT_OK) {
71 71
72 /* xor against DB */ 72 /* xor against DB */
73 for (y = 0; y < (modulus_len - hLen - 1); y++) { 73 for (y = 0; y < (modulus_len - hLen - 1); y++) {
74 DB[y] ^= mask[y]; 74 DB[y] ^= mask[y];
75 } 75 }
76
77 /* now clear the first byte [make sure smaller than modulus] */
78 DB[0] &= 0xFF >> ((modulus_len<<3) - (modulus_bitlen-1));
76 79
77 /* DB = PS || 0x01 || salt, PS == modulus_len - saltlen - hLen - 2 zero bytes */ 80 /* DB = PS || 0x01 || salt, PS == modulus_len - saltlen - hLen - 2 zero bytes */
78 81
79 /* check for zeroes and 0x01 */ 82 /* check for zeroes and 0x01 */
80 for (x = 0; x < modulus_len - saltlen - hLen - 2; x++) { 83 for (x = 0; x < modulus_len - saltlen - hLen - 2; x++) {