1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10 #include "tomcrypt_private.h"
11
12 /**
13 @file rsa_encrypt_key.c
14 RSA PKCS #1 encryption, Tom St Denis and Andreas Lange
15 */
16
17 #ifdef LTC_MRSA
18
19 /**
20 (PKCS #1 v2.0) OAEP pad then encrypt
21 @param in The plaintext
22 @param inlen The length of the plaintext (octets)
23 @param out [out] The ciphertext
24 @param outlen [in/out] The max size and resulting size of the ciphertext
25 @param lparam The system "lparam" for the encryption
26 @param lparamlen The length of lparam (octets)
27 @param prng An active PRNG
28 @param prng_idx The index of the desired prng
29 @param hash_idx The index of the desired hash
30 @param padding Type of padding (LTC_PKCS_1_OAEP or LTC_PKCS_1_V1_5)
31 @param key The RSA key to encrypt to
32 @return CRYPT_OK if successful
33 */
rsa_encrypt_key_ex(const unsigned char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen,const unsigned char * lparam,unsigned long lparamlen,prng_state * prng,int prng_idx,int hash_idx,int padding,const rsa_key * key)34 int rsa_encrypt_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 prng_state *prng, int prng_idx,
38 int hash_idx, int padding,
39 const rsa_key *key)
40 {
41 unsigned long modulus_bitlen, modulus_bytelen, x;
42 int err;
43
44 LTC_ARGCHK(in != NULL);
45 LTC_ARGCHK(out != NULL);
46 LTC_ARGCHK(outlen != NULL);
47 LTC_ARGCHK(key != NULL);
48
49 /* valid padding? */
50 if ((padding != LTC_PKCS_1_V1_5) &&
51 (padding != LTC_PKCS_1_OAEP)) {
52 return CRYPT_PK_INVALID_PADDING;
53 }
54
55 /* valid prng? */
56 if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
57 return err;
58 }
59
60 if (padding == LTC_PKCS_1_OAEP) {
61 /* valid hash? */
62 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
63 return err;
64 }
65 }
66
67 /* get modulus len in bits */
68 modulus_bitlen = mp_count_bits( (key->N));
69
70 /* outlen must be at least the size of the modulus */
71 modulus_bytelen = mp_unsigned_bin_size( (key->N));
72 if (modulus_bytelen > *outlen) {
73 *outlen = modulus_bytelen;
74 return CRYPT_BUFFER_OVERFLOW;
75 }
76
77 if (padding == LTC_PKCS_1_OAEP) {
78 /* OAEP pad the key */
79 x = *outlen;
80 if ((err = pkcs_1_oaep_encode(in, inlen, lparam,
81 lparamlen, modulus_bitlen, prng, prng_idx, hash_idx,
82 out, &x)) != CRYPT_OK) {
83 return err;
84 }
85 } else {
86 /* PKCS #1 v1.5 pad the key */
87 x = *outlen;
88 if ((err = pkcs_1_v1_5_encode(in, inlen, LTC_PKCS_1_EME,
89 modulus_bitlen, prng, prng_idx,
90 out, &x)) != CRYPT_OK) {
91 return err;
92 }
93 }
94
95 /* rsa exptmod the OAEP or PKCS #1 v1.5 pad */
96 return ltc_mp.rsa_me(out, x, out, outlen, PK_PUBLIC, key);
97 }
98
99 #endif /* LTC_MRSA */
100
101 /* ref: $Format:%D$ */
102 /* git commit: $Format:%H$ */
103 /* commit time: $Format:%ai$ */
104