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comparison libtomcrypt/src/pk/rsa/rsa_decrypt_key.c @ 399:a707e6148060

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merge of '5fdf69ca60d1683cdd9f4c2595134bed26394834' and '6b61c50f4cf888bea302ac8fcf5dbb573b443251'
author Matt Johnston <matt@ucc.asn.au>
date Sat, 03 Feb 2007 08:20:34 +0000
parents 0cbe8f6dbf9e
children f849a5ca2efc
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394:17d097fc111c 399:a707e6148060
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file rsa_decrypt_key.c
15 RSA PKCS #1 Decryption, Tom St Denis and Andreas Lange
16 */
17
18 #ifdef MRSA
19
20 /**
21 PKCS #1 decrypt then v1.5 or OAEP depad
22 @param in The ciphertext
23 @param inlen The length of the ciphertext (octets)
24 @param out [out] The plaintext
25 @param outlen [in/out] The max size and resulting size of the plaintext (octets)
26 @param lparam The system "lparam" value
27 @param lparamlen The length of the lparam value (octets)
28 @param hash_idx The index of the hash desired
29 @param padding Type of padding (LTC_PKCS_1_OAEP or LTC_PKCS_1_V1_5)
30 @param stat [out] Result of the decryption, 1==valid, 0==invalid
31 @param key The corresponding private RSA key
32 @return CRYPT_OK if succcessul (even if invalid)
33 */
34 int rsa_decrypt_key_ex(const unsigned char *in, unsigned long inlen,
35 unsigned char *out, unsigned long *outlen,
36 const unsigned char *lparam, unsigned long lparamlen,
37 int hash_idx, int padding,
38 int *stat, rsa_key *key)
39 {
40 unsigned long modulus_bitlen, modulus_bytelen, x;
41 int err;
42 unsigned char *tmp;
43
44 LTC_ARGCHK(out != NULL);
45 LTC_ARGCHK(outlen != NULL);
46 LTC_ARGCHK(key != NULL);
47 LTC_ARGCHK(stat != NULL);
48
49 /* default to invalid */
50 *stat = 0;
51
52 /* valid padding? */
53
54 if ((padding != LTC_PKCS_1_V1_5) &&
55 (padding != LTC_PKCS_1_OAEP)) {
56 return CRYPT_PK_INVALID_PADDING;
57 }
58
59 if (padding == LTC_PKCS_1_OAEP) {
60 /* valid hash ? */
61 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
62 return err;
63 }
64 }
65
66 /* get modulus len in bits */
67 modulus_bitlen = mp_count_bits( (key->N));
68
69 /* outlen must be at least the size of the modulus */
70 modulus_bytelen = mp_unsigned_bin_size( (key->N));
71 if (modulus_bytelen != inlen) {
72 return CRYPT_INVALID_PACKET;
73 }
74
75 /* allocate ram */
76 tmp = XMALLOC(inlen);
77 if (tmp == NULL) {
78 return CRYPT_MEM;
79 }
80
81 /* rsa decode the packet */
82 x = inlen;
83 if ((err = ltc_mp.rsa_me(in, inlen, tmp, &x, PK_PRIVATE, key)) != CRYPT_OK) {
84 XFREE(tmp);
85 return err;
86 }
87
88 if (padding == LTC_PKCS_1_OAEP) {
89 /* now OAEP decode the packet */
90 err = pkcs_1_oaep_decode(tmp, x, lparam, lparamlen, modulus_bitlen, hash_idx,
91 out, outlen, stat);
92 } else {
93 /* now PKCS #1 v1.5 depad the packet */
94 err = pkcs_1_v1_5_decode(tmp, x, LTC_PKCS_1_EME, modulus_bitlen, out, outlen, stat);
95 }
96
97 XFREE(tmp);
98 return err;
99 }
100
101 #endif /* MRSA */
102
103 /* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_decrypt_key.c,v $ */
104 /* $Revision: 1.8 $ */
105 /* $Date: 2006/11/01 09:18:22 $ */