1 /* crypto/rsa/rsa_oaep.c */
2 /* Written by Ulf Moeller. This software is distributed on an "AS IS"
3 basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. */
5 /* EME_OAEP as defined in RFC 2437 (PKCS #1 v2.0) */
14 int MGF1(unsigned char *mask, long len, unsigned char *seed, long seedlen);
16 int RSA_padding_add_PKCS1_OAEP(to, tlen, from, flen, param, plen)
24 int i, emlen = tlen - 1;
25 unsigned char *db, *seed;
26 unsigned char *dbmask, seedmask[SHA_DIGEST_LENGTH];
28 if (flen > emlen - 2 * SHA_DIGEST_LENGTH - 1)
30 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP,
31 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
35 if (emlen < 2 * SHA_DIGEST_LENGTH + 1)
37 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, RSA_R_KEY_SIZE_TOO_SMALL);
41 dbmask = Malloc(emlen - SHA_DIGEST_LENGTH);
44 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
50 db = to + SHA_DIGEST_LENGTH + 1;
52 SHA1(param, plen, db);
53 memset(db + SHA_DIGEST_LENGTH, 0,
54 emlen - flen - 2 * SHA_DIGEST_LENGTH - 1);
55 db[emlen - flen - SHA_DIGEST_LENGTH - 1] = 0x01;
56 memcpy(db + emlen - flen - SHA_DIGEST_LENGTH, from, (unsigned int) flen);
57 RAND_bytes(seed, SHA_DIGEST_LENGTH);
60 "\xaa\xfd\x12\xf6\x59\xca\xe6\x34\x89\xb4\x79\xe5\x07\x6d\xde\xc2\xf0\x6c\xb5\x8f",
64 MGF1(dbmask, emlen - SHA_DIGEST_LENGTH, seed, SHA_DIGEST_LENGTH);
65 for (i = 0; i < emlen - SHA_DIGEST_LENGTH; i++)
68 MGF1(seedmask, SHA_DIGEST_LENGTH, db, emlen - SHA_DIGEST_LENGTH);
69 for (i = 0; i < SHA_DIGEST_LENGTH; i++)
70 seed[i] ^= seedmask[i];
76 int RSA_padding_check_PKCS1_OAEP(to, tlen, from, flen, num, param, plen)
85 int i, dblen, mlen = -1;
86 unsigned char *maskeddb;
87 unsigned char *db, seed[SHA_DIGEST_LENGTH], phash[SHA_DIGEST_LENGTH];
89 if (flen < 2 * SHA_DIGEST_LENGTH + 1)
91 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_OAEP_DECODING_ERROR);
95 dblen = flen - SHA_DIGEST_LENGTH;
99 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
103 maskeddb = from + SHA_DIGEST_LENGTH;
105 MGF1(seed, SHA_DIGEST_LENGTH, maskeddb, dblen);
106 for (i = 0; i < SHA_DIGEST_LENGTH; i++)
109 MGF1(db, dblen, seed, SHA_DIGEST_LENGTH);
110 for (i = 0; i < dblen; i++)
111 db[i] ^= maskeddb[i];
113 SHA1(param, plen, phash);
115 if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0)
116 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_OAEP_DECODING_ERROR);
119 for (i = SHA_DIGEST_LENGTH; i < dblen; i++)
122 if (db[i] != 0x01 || i++ >= dblen)
123 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP,
124 RSA_R_OAEP_DECODING_ERROR);
130 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, RSA_R_DATA_TOO_LARGE);
134 memcpy(to, db + i, mlen);
141 int MGF1(unsigned char *mask, long len, unsigned char *seed, long seedlen)
144 unsigned char cnt[4];
146 unsigned char md[SHA_DIGEST_LENGTH];
148 for (i = 0; outlen < len; i++)
150 cnt[0] = (i >> 24) & 255, cnt[1] = (i >> 16) & 255,
151 cnt[2] = (i >> 8) & 255, cnt[3] = i & 255;
153 SHA1_Update(&c, seed, seedlen);
154 SHA1_Update(&c, cnt, 4);
155 if (outlen + SHA_DIGEST_LENGTH <= len)
157 SHA1_Final(mask + outlen, &c);
158 outlen += SHA_DIGEST_LENGTH;
163 memcpy(mask + outlen, md, len - outlen);