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103 lines
2.6 KiB
C
103 lines
2.6 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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/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b
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*
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* All curves taken from NIST recommendation paper of July 1999
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* Available at http://csrc.nist.gov/cryptval/dss.htm
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*/
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#include "tomcrypt.h"
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/**
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@file ecc_ansi_x963_import.c
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ECC Crypto, Tom St Denis
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*/
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#ifdef LTC_MECC
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/** Import an ANSI X9.63 format public key
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@param in The input data to read
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@param inlen The length of the input data
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@param key [out] destination to store imported key \
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*/
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int ecc_ansi_x963_import(const unsigned char *in, unsigned long inlen, ecc_key *key)
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{
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return ecc_ansi_x963_import_ex(in, inlen, key, NULL);
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}
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int ecc_ansi_x963_import_ex(const unsigned char *in, unsigned long inlen, ecc_key *key, ltc_ecc_set_type *dp)
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{
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int x, err;
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LTC_ARGCHK(in != NULL);
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LTC_ARGCHK(key != NULL);
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/* must be odd */
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if ((inlen & 1) == 0) {
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return CRYPT_INVALID_ARG;
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}
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/* init key */
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if (mp_init_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, NULL) != CRYPT_OK) {
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return CRYPT_MEM;
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}
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/* check for 4, 6 or 7 */
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if (in[0] != 4 && in[0] != 6 && in[0] != 7) {
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err = CRYPT_INVALID_PACKET;
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goto error;
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}
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/* read data */
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if ((err = mp_read_unsigned_bin(key->pubkey.x, (unsigned char *)in+1, (inlen-1)>>1)) != CRYPT_OK) {
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goto error;
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}
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if ((err = mp_read_unsigned_bin(key->pubkey.y, (unsigned char *)in+1+((inlen-1)>>1), (inlen-1)>>1)) != CRYPT_OK) {
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goto error;
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}
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if ((err = mp_set(key->pubkey.z, 1)) != CRYPT_OK) { goto error; }
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if (dp == NULL) {
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/* determine the idx */
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for (x = 0; ltc_ecc_sets[x].size != 0; x++) {
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if ((unsigned)ltc_ecc_sets[x].size >= ((inlen-1)>>1)) {
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break;
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}
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}
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if (ltc_ecc_sets[x].size == 0) {
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err = CRYPT_INVALID_PACKET;
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goto error;
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}
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/* set the idx */
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key->idx = x;
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key->dp = <c_ecc_sets[x];
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} else {
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if (((inlen-1)>>1) != (unsigned long) dp->size) {
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err = CRYPT_INVALID_PACKET;
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goto error;
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}
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key->idx = -1;
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key->dp = dp;
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}
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key->type = PK_PUBLIC;
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/* we're done */
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return CRYPT_OK;
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error:
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mp_clear_multi(key->pubkey.x, key->pubkey.y, key->pubkey.z, key->k, NULL);
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return err;
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}
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#endif
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/* ref: HEAD -> master, tag: v1.18.2 */
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/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
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/* commit time: 2018-07-01 22:49:01 +0200 */
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