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trezor-firmware/embed/extmod/modtrezorcrypto/modtrezorcrypto-secp256k1.h

247 lines
9.1 KiB
C

/*
* This file is part of the TREZOR project, https://trezor.io/
*
* Copyright (c) SatoshiLabs
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "py/objstr.h"
#include "ecdsa.h"
#include "secp256k1.h"
/// package: trezorcrypto.secp256k1
/// def generate_secret() -> bytes:
/// '''
/// Generate secret key.
/// '''
STATIC mp_obj_t mod_trezorcrypto_secp256k1_generate_secret() {
uint8_t out[32];
for (;;) {
random_buffer(out, 32);
// check whether secret > 0 && secret < curve_order
if (0 ==
memcmp(
out,
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
32))
continue;
if (0 <=
memcmp(
out,
"\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFE"
"\xBA\xAE\xDC\xE6\xAF\x48\xA0\x3B\xBF\xD2\x5E\x8C\xD0\x36\x41\x41",
32))
continue;
break;
}
return mp_obj_new_bytes(out, sizeof(out));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorcrypto_secp256k1_generate_secret_obj,
mod_trezorcrypto_secp256k1_generate_secret);
/// def publickey(secret_key: bytes, compressed: bool = True) -> bytes:
/// '''
/// Computes public key from secret key.
/// '''
STATIC mp_obj_t mod_trezorcrypto_secp256k1_publickey(size_t n_args,
const mp_obj_t *args) {
mp_buffer_info_t sk;
mp_get_buffer_raise(args[0], &sk, MP_BUFFER_READ);
if (sk.len != 32) {
mp_raise_ValueError("Invalid length of secret key");
}
bool compressed = n_args < 2 || args[1] == mp_const_true;
if (compressed) {
uint8_t out[33];
ecdsa_get_public_key33(&secp256k1, (const uint8_t *)sk.buf, out);
return mp_obj_new_bytes(out, sizeof(out));
} else {
uint8_t out[65];
ecdsa_get_public_key65(&secp256k1, (const uint8_t *)sk.buf, out);
return mp_obj_new_bytes(out, sizeof(out));
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(
mod_trezorcrypto_secp256k1_publickey_obj, 1, 2,
mod_trezorcrypto_secp256k1_publickey);
static int ethereum_is_canonical(uint8_t v, uint8_t signature[64]) {
(void)signature;
return (v & 2) == 0;
}
enum {
CANONICAL_SIG_ETHEREUM = 1,
};
/// def sign(secret_key: bytes, digest: bytes, compressed: bool = True,
/// canonical: int = None) -> bytes:
/// '''
/// Uses secret key to produce the signature of the digest.
/// '''
STATIC mp_obj_t mod_trezorcrypto_secp256k1_sign(size_t n_args,
const mp_obj_t *args) {
mp_buffer_info_t sk, dig;
mp_get_buffer_raise(args[0], &sk, MP_BUFFER_READ);
mp_get_buffer_raise(args[1], &dig, MP_BUFFER_READ);
bool compressed = (n_args < 3) || (args[2] == mp_const_true);
mp_int_t canonical = (n_args > 3) ? mp_obj_get_int(args[3]) : 0;
int (*is_canonical)(uint8_t by, uint8_t sig[64]) = NULL;
switch (canonical) {
case CANONICAL_SIG_ETHEREUM:
is_canonical = ethereum_is_canonical;
break;
}
if (sk.len != 32) {
mp_raise_ValueError("Invalid length of secret key");
}
if (dig.len != 32) {
mp_raise_ValueError("Invalid length of digest");
}
uint8_t out[65], pby;
if (0 != ecdsa_sign_digest(&secp256k1, (const uint8_t *)sk.buf,
(const uint8_t *)dig.buf, out + 1, &pby,
is_canonical)) {
mp_raise_ValueError("Signing failed");
}
out[0] = 27 + pby + compressed * 4;
return mp_obj_new_bytes(out, sizeof(out));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorcrypto_secp256k1_sign_obj,
2, 4,
mod_trezorcrypto_secp256k1_sign);
/// def verify(public_key: bytes, signature: bytes, digest: bytes) -> bool:
/// '''
/// Uses public key to verify the signature of the digest.
/// Returns True on success.
/// '''
STATIC mp_obj_t mod_trezorcrypto_secp256k1_verify(mp_obj_t public_key,
mp_obj_t signature,
mp_obj_t digest) {
mp_buffer_info_t pk, sig, dig;
mp_get_buffer_raise(public_key, &pk, MP_BUFFER_READ);
mp_get_buffer_raise(signature, &sig, MP_BUFFER_READ);
mp_get_buffer_raise(digest, &dig, MP_BUFFER_READ);
if (pk.len != 33 && pk.len != 65) {
mp_raise_ValueError("Invalid length of public key");
}
if (sig.len != 64 && sig.len != 65) {
mp_raise_ValueError("Invalid length of signature");
}
int offset = sig.len - 64;
if (dig.len != 32) {
mp_raise_ValueError("Invalid length of digest");
}
return mp_obj_new_bool(
0 == ecdsa_verify_digest(&secp256k1, (const uint8_t *)pk.buf,
(const uint8_t *)sig.buf + offset,
(const uint8_t *)dig.buf));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_trezorcrypto_secp256k1_verify_obj,
mod_trezorcrypto_secp256k1_verify);
/// def verify_recover(signature: bytes, digest: bytes) -> bytes:
/// '''
/// Uses signature of the digest to verify the digest and recover the public
/// key. Returns public key on success, None on failure.
/// '''
STATIC mp_obj_t mod_trezorcrypto_secp256k1_verify_recover(mp_obj_t signature,
mp_obj_t digest) {
mp_buffer_info_t sig, dig;
mp_get_buffer_raise(signature, &sig, MP_BUFFER_READ);
mp_get_buffer_raise(digest, &dig, MP_BUFFER_READ);
if (sig.len != 65) {
mp_raise_ValueError("Invalid length of signature");
}
if (dig.len != 32) {
mp_raise_ValueError("Invalid length of digest");
}
uint8_t recid = ((const uint8_t *)sig.buf)[0] - 27;
if (recid >= 8) {
mp_raise_ValueError("Invalid recid in signature");
}
bool compressed = (recid >= 4);
recid &= 3;
uint8_t out[65];
if (0 == ecdsa_recover_pub_from_sig(&secp256k1, out,
(const uint8_t *)sig.buf + 1,
(const uint8_t *)dig.buf, recid)) {
if (compressed) {
out[0] = 0x02 | (out[64] & 1);
return mp_obj_new_bytes(out, 33);
}
return mp_obj_new_bytes(out, sizeof(out));
} else {
return mp_const_none;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_secp256k1_verify_recover_obj,
mod_trezorcrypto_secp256k1_verify_recover);
/// def multiply(secret_key: bytes, public_key: bytes) -> bytes:
/// '''
/// Multiplies point defined by public_key with scalar defined by
/// secret_key. Useful for ECDH.
/// '''
STATIC mp_obj_t mod_trezorcrypto_secp256k1_multiply(mp_obj_t secret_key,
mp_obj_t public_key) {
mp_buffer_info_t sk, pk;
mp_get_buffer_raise(secret_key, &sk, MP_BUFFER_READ);
mp_get_buffer_raise(public_key, &pk, MP_BUFFER_READ);
if (sk.len != 32) {
mp_raise_ValueError("Invalid length of secret key");
}
if (pk.len != 33 && pk.len != 65) {
mp_raise_ValueError("Invalid length of public key");
}
uint8_t out[65];
if (0 != ecdh_multiply(&secp256k1, (const uint8_t *)sk.buf,
(const uint8_t *)pk.buf, out)) {
mp_raise_ValueError("Multiply failed");
}
return mp_obj_new_bytes(out, sizeof(out));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_secp256k1_multiply_obj,
mod_trezorcrypto_secp256k1_multiply);
STATIC const mp_rom_map_elem_t mod_trezorcrypto_secp256k1_globals_table[] = {
{MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_secp256k1)},
{MP_ROM_QSTR(MP_QSTR_generate_secret),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_generate_secret_obj)},
{MP_ROM_QSTR(MP_QSTR_publickey),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_publickey_obj)},
{MP_ROM_QSTR(MP_QSTR_sign),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_sign_obj)},
{MP_ROM_QSTR(MP_QSTR_verify),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_verify_obj)},
{MP_ROM_QSTR(MP_QSTR_verify_recover),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_verify_recover_obj)},
{MP_ROM_QSTR(MP_QSTR_multiply),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_multiply_obj)},
{MP_ROM_QSTR(MP_QSTR_CANONICAL_SIG_ETHEREUM),
MP_OBJ_NEW_SMALL_INT(CANONICAL_SIG_ETHEREUM)},
};
STATIC MP_DEFINE_CONST_DICT(mod_trezorcrypto_secp256k1_globals,
mod_trezorcrypto_secp256k1_globals_table);
STATIC const mp_obj_module_t mod_trezorcrypto_secp256k1_module = {
.base = {&mp_type_module},
.globals = (mp_obj_dict_t *)&mod_trezorcrypto_secp256k1_globals,
};