75 lines
2.1 KiB
C
75 lines
2.1 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 ecc_make_key.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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/**
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Make a new ECC key
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@param prng An active PRNG state
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@param wprng The index of the PRNG you wish to use
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@param keysize The keysize for the new key (in octets from 20 to 65 bytes)
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@param key [out] Destination of the newly created key
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@return CRYPT_OK if successful, upon error all allocated memory will be freed
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*/
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int ecc_make_key(prng_state *prng, int wprng, int keysize, ecc_key *key)
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{
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int err;
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if ((err = ecc_set_curve_by_size(keysize, key)) != CRYPT_OK) { return err; }
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if ((err = ecc_generate_key(prng, wprng, key)) != CRYPT_OK) { return err; }
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return CRYPT_OK;
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}
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int ecc_make_key_ex(prng_state *prng, int wprng, ecc_key *key, const ltc_ecc_curve *cu)
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{
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int err;
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if ((err = ecc_set_curve(cu, key)) != CRYPT_OK) { return err; }
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if ((err = ecc_generate_key(prng, wprng, key)) != CRYPT_OK) { return err; }
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return CRYPT_OK;
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}
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int ecc_generate_key(prng_state *prng, int wprng, ecc_key *key)
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{
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int err;
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LTC_ARGCHK(ltc_mp.name != NULL);
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LTC_ARGCHK(key != NULL);
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LTC_ARGCHK(key->dp.size > 0);
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/* ECC key pair generation according to FIPS-186-4 (B.4.2 Key Pair Generation by Testing Candidates):
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* the generated private key k should be the range [1, order-1]
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* a/ N = bitlen(order)
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* b/ generate N random bits and convert them into big integer k
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* c/ if k not in [1, order-1] go to b/
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* e/ Q = k*G
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*/
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if ((err = rand_bn_upto(key->k, key->dp.order, prng, wprng)) != CRYPT_OK) {
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goto error;
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}
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/* make the public key */
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if ((err = ltc_mp.ecc_ptmul(key->k, &key->dp.base, &key->pubkey, key->dp.A, key->dp.prime, 1)) != CRYPT_OK) {
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goto error;
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}
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key->type = PK_PRIVATE;
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key->rfc6979_hash_alg = NULL;
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/* success */
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err = CRYPT_OK;
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goto cleanup;
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error:
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ecc_free(key);
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cleanup:
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return err;
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}
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#endif
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