274 lines
6.6 KiB
C
274 lines
6.6 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
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*/
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/* RSA Code by Tom St Denis */
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#include "mycrypt.h"
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#ifdef MRSA
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int rsa_signpad(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen)
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{
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unsigned long x, y;
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_ARGCHK(in != NULL);
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_ARGCHK(out != NULL);
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_ARGCHK(outlen != NULL);
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if (*outlen < (3 * inlen)) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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/* check inlen */
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if (inlen > MAX_RSA_SIZE/8) {
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return CRYPT_PK_INVALID_SIZE;
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}
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for (y = x = 0; x < inlen; x++)
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out[y++] = (unsigned char)0xFF;
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for (x = 0; x < inlen; x++)
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out[y++] = in[x];
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for (x = 0; x < inlen; x++)
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out[y++] = (unsigned char)0xFF;
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*outlen = 3 * inlen;
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return CRYPT_OK;
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}
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int rsa_pad(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen,
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int wprng, prng_state *prng)
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{
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unsigned char buf[3*(MAX_RSA_SIZE/8)];
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unsigned long x;
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int err;
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_ARGCHK(in != NULL);
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_ARGCHK(out != NULL);
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_ARGCHK(outlen != NULL);
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/* is output big enough? */
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if (*outlen < (3 * inlen)) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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/* get random padding required */
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if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
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return err;
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}
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/* check inlen */
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if (inlen > (MAX_RSA_SIZE/8)) {
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return CRYPT_PK_INVALID_SIZE;
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}
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if (prng_descriptor[wprng].read(buf, inlen*2-2, prng) != (inlen*2 - 2)) {
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return CRYPT_ERROR_READPRNG;
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}
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/* pad it like a sandwhich
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*
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* Looks like 0xFF R1 M R2 0xFF
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*
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* Where R1/R2 are random and exactly equal to the length of M minus one byte.
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*/
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for (x = 0; x < inlen-1; x++) {
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out[x+1] = buf[x];
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}
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for (x = 0; x < inlen; x++) {
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out[x+inlen] = in[x];
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}
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for (x = 0; x < inlen-1; x++) {
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out[x+inlen+inlen] = buf[x+inlen-1];
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}
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/* last and first bytes are 0xFF */
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out[0] = out[inlen+inlen+inlen-1] = (unsigned char)0xFF;
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/* clear up and return */
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#ifdef CLEAN_STACK
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zeromem(buf, sizeof(buf));
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#endif
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*outlen = inlen*3;
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return CRYPT_OK;
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}
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int rsa_signdepad(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen)
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{
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unsigned long x;
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_ARGCHK(in != NULL);
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_ARGCHK(out != NULL);
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_ARGCHK(outlen != NULL);
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if (*outlen < inlen/3) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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/* check padding bytes */
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for (x = 0; x < inlen/3; x++) {
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if (in[x] != (unsigned char)0xFF || in[x+(inlen/3)+(inlen/3)] != (unsigned char)0xFF) {
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return CRYPT_INVALID_PACKET;
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}
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}
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for (x = 0; x < inlen/3; x++) {
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out[x] = in[x+(inlen/3)];
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}
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*outlen = inlen/3;
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return CRYPT_OK;
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}
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int rsa_depad(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen)
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{
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unsigned long x;
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_ARGCHK(in != NULL);
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_ARGCHK(out != NULL);
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_ARGCHK(outlen != NULL);
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if (*outlen < inlen/3) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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for (x = 0; x < inlen/3; x++) {
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out[x] = in[x+(inlen/3)];
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}
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*outlen = inlen/3;
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return CRYPT_OK;
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}
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int rsa_export(unsigned char *out, unsigned long *outlen, int type, rsa_key *key)
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{
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unsigned long y, z;
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int err;
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_ARGCHK(out != NULL);
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_ARGCHK(outlen != NULL);
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_ARGCHK(key != NULL);
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/* can we store the static header? */
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if (*outlen < (PACKET_SIZE + 1)) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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/* type valid? */
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if (!(key->type == PK_PRIVATE || key->type == PK_PRIVATE_OPTIMIZED) &&
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(type == PK_PRIVATE || type == PK_PRIVATE_OPTIMIZED)) {
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return CRYPT_PK_INVALID_TYPE;
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}
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/* start at offset y=PACKET_SIZE */
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y = PACKET_SIZE;
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/* output key type */
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out[y++] = type;
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/* output modulus */
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OUTPUT_BIGNUM(&key->N, out, y, z);
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/* output public key */
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OUTPUT_BIGNUM(&key->e, out, y, z);
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if (type == PK_PRIVATE || type == PK_PRIVATE_OPTIMIZED) {
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OUTPUT_BIGNUM(&key->d, out, y, z);
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}
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if (type == PK_PRIVATE_OPTIMIZED) {
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OUTPUT_BIGNUM(&key->dQ, out, y, z);
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OUTPUT_BIGNUM(&key->dP, out, y, z);
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OUTPUT_BIGNUM(&key->pQ, out, y, z);
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OUTPUT_BIGNUM(&key->qP, out, y, z);
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OUTPUT_BIGNUM(&key->p, out, y, z);
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OUTPUT_BIGNUM(&key->q, out, y, z);
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}
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/* store packet header */
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packet_store_header(out, PACKET_SECT_RSA, PACKET_SUB_KEY);
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/* copy to the user buffer */
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*outlen = y;
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/* clear stack and return */
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return CRYPT_OK;
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}
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int rsa_import(const unsigned char *in, unsigned long inlen, rsa_key *key)
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{
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unsigned long x, y;
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int err;
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_ARGCHK(in != NULL);
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_ARGCHK(key != NULL);
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/* check length */
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if (inlen < (1+PACKET_SIZE)) {
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return CRYPT_INVALID_PACKET;
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}
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/* test packet header */
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if ((err = packet_valid_header((unsigned char *)in, PACKET_SECT_RSA, PACKET_SUB_KEY)) != CRYPT_OK) {
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return err;
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}
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/* init key */
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if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP, &key->qP,
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&key->pQ, &key->p, &key->q, NULL)) != MP_OKAY) {
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return mpi_to_ltc_error(err);
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}
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/* get key type */
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y = PACKET_SIZE;
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key->type = (int)in[y++];
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/* load the modulus */
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INPUT_BIGNUM(&key->N, in, x, y, inlen);
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/* load public exponent */
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INPUT_BIGNUM(&key->e, in, x, y, inlen);
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/* get private exponent */
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if (key->type == PK_PRIVATE || key->type == PK_PRIVATE_OPTIMIZED) {
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INPUT_BIGNUM(&key->d, in, x, y, inlen);
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}
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/* get CRT private data if required */
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if (key->type == PK_PRIVATE_OPTIMIZED) {
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INPUT_BIGNUM(&key->dQ, in, x, y, inlen);
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INPUT_BIGNUM(&key->dP, in, x, y, inlen);
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INPUT_BIGNUM(&key->pQ, in, x, y, inlen);
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INPUT_BIGNUM(&key->qP, in, x, y, inlen);
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INPUT_BIGNUM(&key->p, in, x, y, inlen);
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INPUT_BIGNUM(&key->q, in, x, y, inlen);
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}
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/* free up ram not required */
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if (key->type != PK_PRIVATE_OPTIMIZED) {
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mp_clear_multi(&key->dQ, &key->dP, &key->pQ, &key->qP, &key->p, &key->q, NULL);
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}
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if (key->type != PK_PRIVATE && key->type != PK_PRIVATE_OPTIMIZED) {
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mp_clear(&key->d);
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}
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return CRYPT_OK;
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error:
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mp_clear_multi(&key->d, &key->e, &key->N, &key->dQ, &key->dP,
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&key->pQ, &key->qP, &key->p, &key->q, NULL);
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return err;
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}
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#include "rsa_sys.c"
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#endif /* RSA */
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