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, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11#include "tomcrypt.h"
12
13/**
14  @file rsa_encrypt_key.c
15  RSA PKCS #1 encryption, Tom St Denis and Andreas Lange
16*/
17
18#ifdef MRSA
19
20/**
21    (PKCS #1 v2.0) OAEP pad then encrypt
22    @param in          The plaintext
23    @param inlen       The length of the plaintext (octets)
24    @param out         [out] The ciphertext
25    @param outlen      [in/out] The max size and resulting size of the ciphertext
26    @param lparam      The system "lparam" for the encryption
27    @param lparamlen   The length of lparam (octets)
28    @param prng        An active PRNG
29    @param prng_idx    The index of the desired prng
30    @param hash_idx    The index of the desired hash
31    @param padding     Type of padding (LTC_PKCS_1_OAEP or LTC_PKCS_1_V1_5)
32    @param key         The RSA key to encrypt to
33    @return CRYPT_OK if successful
34*/
35int rsa_encrypt_key_ex(const unsigned char *in,     unsigned long inlen,
36                             unsigned char *out,    unsigned long *outlen,
37                       const unsigned char *lparam, unsigned long lparamlen,
38                       prng_state *prng, int prng_idx, int hash_idx, int padding, rsa_key *key)
39{
40  unsigned long modulus_bitlen, modulus_bytelen, x;
41  int           err;
42
43  LTC_ARGCHK(in     != NULL);
44  LTC_ARGCHK(out    != NULL);
45  LTC_ARGCHK(outlen != NULL);
46  LTC_ARGCHK(key    != NULL);
47
48  /* valid padding? */
49  if ((padding != LTC_PKCS_1_V1_5) &&
50      (padding != LTC_PKCS_1_OAEP)) {
51    return CRYPT_PK_INVALID_PADDING;
52  }
53
54  /* valid prng? */
55  if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
56     return err;
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 > *outlen) {
72     *outlen = modulus_bytelen;
73     return CRYPT_BUFFER_OVERFLOW;
74  }
75
76  if (padding == LTC_PKCS_1_OAEP) {
77    /* OAEP pad the key */
78    x = *outlen;
79    if ((err = pkcs_1_oaep_encode(in, inlen, lparam,
80                                  lparamlen, modulus_bitlen, prng, prng_idx, hash_idx,
81                                  out, &x)) != CRYPT_OK) {
82       return err;
83    }
84  } else {
85    /* PKCS #1 v1.5 pad the key */
86    x = *outlen;
87    if ((err = pkcs_1_v1_5_encode(in, inlen, LTC_PKCS_1_EME,
88                                  modulus_bitlen, prng, prng_idx,
89                                  out, &x)) != CRYPT_OK) {
90      return err;
91    }
92  }
93
94  /* rsa exptmod the OAEP or PKCS #1 v1.5 pad */
95  return ltc_mp.rsa_me(out, x, out, outlen, PK_PUBLIC, key);
96}
97
98#endif /* MRSA */
99
100/* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_encrypt_key.c,v $ */
101/* $Revision: 1.8 $ */
102/* $Date: 2006/11/01 09:18:22 $ */
103