94 lines
3.0 KiB
C
94 lines
3.0 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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/**
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@file rsa_encrypt_key.c
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RSA PKCS #1 encryption, Tom St Denis and Andreas Lange
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*/
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#ifdef LTC_MRSA
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/**
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(PKCS #1 v2.0) OAEP pad then encrypt
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@param in The plaintext
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@param inlen The length of the plaintext (octets)
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@param out [out] The ciphertext
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@param outlen [in/out] The max size and resulting size of the ciphertext
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@param lparam The system "lparam" for the encryption
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@param lparamlen The length of lparam (octets)
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@param prng An active PRNG
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@param prng_idx The index of the desired prng
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@param hash_idx The index of the desired hash
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@param padding Type of padding (LTC_PKCS_1_OAEP or LTC_PKCS_1_V1_5)
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@param key The RSA key to encrypt to
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@return CRYPT_OK if successful
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*/
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int rsa_encrypt_key_ex(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen,
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const unsigned char *lparam, unsigned long lparamlen,
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prng_state *prng, int prng_idx,
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int mgf_hash, int lparam_hash,
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int padding,
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const rsa_key *key)
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{
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unsigned long modulus_bitlen, modulus_bytelen, x;
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int err;
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LTC_ARGCHK((inlen == 0) || (in != NULL));
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LTC_ARGCHK(out != NULL);
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LTC_ARGCHK(outlen != NULL);
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LTC_ARGCHK(key != NULL);
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/* valid padding? */
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if ((padding != LTC_PKCS_1_V1_5) &&
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(padding != LTC_PKCS_1_OAEP)) {
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return CRYPT_PK_INVALID_PADDING;
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}
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/* valid prng? */
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if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
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return err;
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}
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if (padding == LTC_PKCS_1_OAEP) {
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/* valid hash? */
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if ((err = hash_is_valid(mgf_hash)) != CRYPT_OK) {
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return err;
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}
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}
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/* get modulus len in bits */
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modulus_bitlen = ltc_mp_count_bits( (key->N));
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/* outlen must be at least the size of the modulus */
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modulus_bytelen = ltc_mp_unsigned_bin_size( (key->N));
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if (modulus_bytelen > *outlen) {
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*outlen = modulus_bytelen;
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return CRYPT_BUFFER_OVERFLOW;
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}
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if (padding == LTC_PKCS_1_OAEP) {
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/* OAEP pad the key */
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x = *outlen;
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if ((err = pkcs_1_oaep_encode(in, inlen, lparam,
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lparamlen, modulus_bitlen, prng, prng_idx, mgf_hash,
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lparam_hash, out, &x)) != CRYPT_OK) {
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return err;
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}
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} else {
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/* PKCS #1 v1.5 pad the key */
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x = *outlen;
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if ((err = pkcs_1_v1_5_encode(in, inlen, LTC_PKCS_1_EME,
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modulus_bitlen, prng, prng_idx,
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out, &x)) != CRYPT_OK) {
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return err;
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}
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}
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/* rsa exptmod the OAEP or PKCS #1 v1.5 pad */
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return ltc_mp.rsa_me(out, x, out, outlen, PK_PUBLIC, key);
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}
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#endif /* LTC_MRSA */
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