int ecc_make_key (void *random_ctx, nettle_random_func random, ecc_key * key, const ecc_set_type * dp) { mpz_t prime, order, Gx, Gy, A, B; int err; /* setup the key variables */ if ((err = mp_init_multi (&prime, &order, &A, &B, &Gx, &Gy, NULL)) != 0) { goto cleanup; } /* read in the specs for this key */ mpz_set_str (prime, (char *) dp->prime, 16); mpz_set_str (order, (char *) dp->order, 16); mpz_set_str (Gx, (char *) dp->Gx, 16); mpz_set_str (Gy, (char *) dp->Gy, 16); mpz_set_str (A, (char *) dp->A, 16); mpz_set_str (B, (char *) dp->B, 16); err = ecc_make_key_ex (random_ctx, random, key, prime, order, A, B, Gx, Gy, 0); mp_clear_multi (&prime, &order, &A, &B, &Gx, &Gy, NULL); cleanup: return err; }
DLL_EXPORT int ECDHEMakeKey(char *x, char *y, char *z, char *k) { ecc_key ecc_dhe; init_dependencies(); int res = ecc_make_key_ex(NULL, find_prng("sprng"), &ecc_dhe, &ecc256); if (!res) { mp_toradix(ecc_dhe.pubkey.x, x, 16); mp_toradix(ecc_dhe.pubkey.y, y, 16); mp_toradix(ecc_dhe.pubkey.z, z, 16); mp_toradix(ecc_dhe.k, k, 16); ecc_free(&ecc_dhe); } }
/** Make a new ECC key @param prng An active PRNG state @param wprng The index of the PRNG you wish to use @param keysize The keysize for the new key (in octets from 20 to 65 bytes) @param key [out] Destination of the newly created key @return CRYPT_OK if successful, upon error all allocated memory will be freed */ int ecc_make_key(prng_state *prng, int wprng, int keysize, ecc_key *key) { int x, err; /* find key size */ for (x = 0; (keysize > ltc_ecc_sets[x].size) && (ltc_ecc_sets[x].size != 0); x++); keysize = ltc_ecc_sets[x].size; if (keysize > ECC_MAXSIZE || ltc_ecc_sets[x].size == 0) { return CRYPT_INVALID_KEYSIZE; } err = ecc_make_key_ex(prng, wprng, key, <c_ecc_sets[x]); key->idx = x; return err; }
/** Encrypt a symmetric key with ECC @param in The symmetric key you want to encrypt @param inlen The length of the key to encrypt (octets) @param out [out] The destination for the ciphertext @param outlen [in/out] The max size and resulting size of the ciphertext @param prng An active PRNG state @param wprng The index of the PRNG you wish to use @param hash The index of the hash you want to use @param key The ECC key you want to encrypt to @return CRYPT_OK if successful */ int ecc_encrypt_key(const unsigned char *in, unsigned long inlen, unsigned char *out, unsigned long *outlen, prng_state *prng, int wprng, int hash, ecc_key *key) { unsigned char *pub_expt, *ecc_shared, *skey; ecc_key pubkey; unsigned long x, y, pubkeysize; int err; LTC_ARGCHK(in != NULL); LTC_ARGCHK(out != NULL); LTC_ARGCHK(outlen != NULL); LTC_ARGCHK(key != NULL); /* check that wprng/cipher/hash are not invalid */ if ((err = prng_is_valid(wprng)) != CRYPT_OK) { return err; } if ((err = hash_is_valid(hash)) != CRYPT_OK) { return err; } if (inlen > hash_descriptor[hash].hashsize) { return CRYPT_INVALID_HASH; } /* make a random key and export the public copy */ if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) { return err; } pub_expt = XMALLOC(ECC_BUF_SIZE); ecc_shared = XMALLOC(ECC_BUF_SIZE); skey = XMALLOC(MAXBLOCKSIZE); if (pub_expt == NULL || ecc_shared == NULL || skey == NULL) { if (pub_expt != NULL) { XFREE(pub_expt); } if (ecc_shared != NULL) { XFREE(ecc_shared); } if (skey != NULL) { XFREE(skey); } ecc_free(&pubkey); return CRYPT_MEM; } pubkeysize = ECC_BUF_SIZE; if ((err = ecc_export(pub_expt, &pubkeysize, PK_PUBLIC, &pubkey)) != CRYPT_OK) { ecc_free(&pubkey); goto LBL_ERR; } /* make random key */ x = ECC_BUF_SIZE; if ((err = ecc_shared_secret(&pubkey, key, ecc_shared, &x)) != CRYPT_OK) { ecc_free(&pubkey); goto LBL_ERR; } ecc_free(&pubkey); y = MAXBLOCKSIZE; if ((err = hash_memory(hash, ecc_shared, x, skey, &y)) != CRYPT_OK) { goto LBL_ERR; } /* Encrypt key */ for (x = 0; x < inlen; x++) { skey[x] ^= in[x]; } err = der_encode_sequence_multi(out, outlen, LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash].OIDlen, hash_descriptor[hash].OID, LTC_ASN1_OCTET_STRING, pubkeysize, pub_expt, LTC_ASN1_OCTET_STRING, inlen, skey, LTC_ASN1_EOL, 0UL, NULL); LBL_ERR: #ifdef LTC_CLEAN_STACK /* clean up */ zeromem(pub_expt, ECC_BUF_SIZE); zeromem(ecc_shared, ECC_BUF_SIZE); zeromem(skey, MAXBLOCKSIZE); #endif XFREE(skey); XFREE(ecc_shared); XFREE(pub_expt); return err; }
/** Sign a message digest @param in The message digest to sign @param inlen The length of the digest @param out [out] The destination for the signature @param outlen [in/out] The max size and resulting size of the signature @param prng An active PRNG state @param wprng The index of the PRNG you wish to use @param key A private ECC key @return CRYPT_OK if successful */ int ecc_sign_hash(const unsigned char *in, unsigned long inlen, unsigned char *out, unsigned long *outlen, prng_state *prng, int wprng, ecc_key *key) { ecc_key pubkey; void *r, *s, *e, *p; int err; LTC_ARGCHK(in != NULL); LTC_ARGCHK(out != NULL); LTC_ARGCHK(outlen != NULL); LTC_ARGCHK(key != NULL); /* is this a private key? */ if (key->type != PK_PRIVATE) { return CRYPT_PK_NOT_PRIVATE; } /* is the IDX valid ? */ if (ltc_ecc_is_valid_idx(key->idx) != 1) { return CRYPT_PK_INVALID_TYPE; } if ((err = prng_is_valid(wprng)) != CRYPT_OK) { return err; } /* get the hash and load it as a bignum into 'e' */ /* init the bignums */ if ((err = mp_init_multi(&r, &s, &p, &e, NULL)) != CRYPT_OK) { return err; } if ((err = mp_read_radix(p, (char *)key->dp->order, 16)) != CRYPT_OK) { goto errnokey; } if ((err = mp_read_unsigned_bin(e, (unsigned char *)in, (int)inlen)) != CRYPT_OK) { goto errnokey; } /* make up a key and export the public copy */ for (;;) { if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) { goto errnokey; } /* find r = x1 mod n */ if ((err = mp_mod(pubkey.pubkey.x, p, r)) != CRYPT_OK) { goto error; } if (mp_iszero(r) == LTC_MP_YES) { ecc_free(&pubkey); } else { /* find s = (e + xr)/k */ if ((err = mp_invmod(pubkey.k, p, pubkey.k)) != CRYPT_OK) { goto error; } /* k = 1/k */ if ((err = mp_mulmod(key->k, r, p, s)) != CRYPT_OK) { goto error; } /* s = xr */ if ((err = mp_add(e, s, s)) != CRYPT_OK) { goto error; } /* s = e + xr */ if ((err = mp_mod(s, p, s)) != CRYPT_OK) { goto error; } /* s = e + xr */ if ((err = mp_mulmod(s, pubkey.k, p, s)) != CRYPT_OK) { goto error; } /* s = (e + xr)/k */ ecc_free(&pubkey); if (mp_iszero(s) == LTC_MP_NO) { break; } } } /* store as SEQUENCE { r, s -- integer } */ err = der_encode_sequence_multi(out, outlen, LTC_ASN1_INTEGER, 1UL, r, LTC_ASN1_INTEGER, 1UL, s, LTC_ASN1_EOL, 0UL, NULL); goto errnokey; error: ecc_free(&pubkey); errnokey: mp_clear_multi(r, s, p, e, NULL); return err; }