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trezor-firmware/micropython/extmod/modtrezorcrypto/modtrezorcrypto-secp256k1.h
2017-02-06 15:40:25 +01:00

190 lines
8.1 KiB
C

/*
* Copyright (c) Pavol Rusnak, SatoshiLabs
*
* Licensed under TREZOR License
* see LICENSE file for details
*/
#include "py/objstr.h"
#include "trezor-crypto/ecdsa.h"
#include "trezor-crypto/secp256k1.h"
typedef struct _mp_obj_Secp256k1_t {
mp_obj_base_t base;
} mp_obj_Secp256k1_t;
STATIC mp_obj_t mod_TrezorCrypto_Secp256k1_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 0, 0, false);
mp_obj_Secp256k1_t *o = m_new_obj(mp_obj_Secp256k1_t);
o->base.type = type;
return MP_OBJ_FROM_PTR(o);
}
/// def trezor.crypto.curve.secp256k1.generate_secret() -> bytes:
/// '''
/// Generate secret key.
/// '''
STATIC mp_obj_t mod_TrezorCrypto_Secp256k1_generate_secret(mp_obj_t self) {
vstr_t vstr;
vstr_init_len(&vstr, 32);
for (;;) {
random_buffer((uint8_t *)vstr.buf, 32);
// check whether secret > 0 && secret < curve_order
if (0 == memcmp(vstr.buf, "\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(vstr.buf, "\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_str_from_vstr(&mp_type_bytes, &vstr);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_TrezorCrypto_Secp256k1_generate_secret_obj, mod_TrezorCrypto_Secp256k1_generate_secret);
/// def trezor.crypto.curve.secp256k1.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[1], &sk, MP_BUFFER_READ);
if (sk.len != 32) {
mp_raise_ValueError("Invalid length of secret key");
}
bool compressed = n_args < 3 || args[2] == mp_const_true;
vstr_t vstr;
if (compressed) {
vstr_init_len(&vstr, 33);
ecdsa_get_public_key33(&secp256k1, (const uint8_t *)sk.buf, (uint8_t *)vstr.buf);
} else {
vstr_init_len(&vstr, 65);
ecdsa_get_public_key65(&secp256k1, (const uint8_t *)sk.buf, (uint8_t *)vstr.buf);
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_TrezorCrypto_Secp256k1_publickey_obj, 2, 3, mod_TrezorCrypto_Secp256k1_publickey);
/// def trezor.crypto.curve.secp256k1.sign(secret_key: bytes, digest: bytes, compressed: bool=True) -> 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[1], &sk, MP_BUFFER_READ);
mp_get_buffer_raise(args[2], &dig, MP_BUFFER_READ);
bool compressed = n_args < 4 || args[3] == mp_const_true;
if (sk.len != 32) {
mp_raise_ValueError("Invalid length of secret key");
}
if (dig.len != 32) {
mp_raise_ValueError("Invalid length of digest");
}
vstr_t vstr;
vstr_init_len(&vstr, 65);
uint8_t pby;
if (0 != ecdsa_sign_digest(&secp256k1, (const uint8_t *)sk.buf, (const uint8_t *)dig.buf, (uint8_t *)vstr.buf + 1, &pby, NULL)) {
mp_raise_ValueError("Signing failed");
}
vstr.buf[0] = 27 + pby + compressed * 4;
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_TrezorCrypto_Secp256k1_sign_obj, 3, 4, mod_TrezorCrypto_Secp256k1_sign);
/// def trezor.crypto.curve.secp256k1.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(size_t n_args, const mp_obj_t *args) {
mp_buffer_info_t pk, sig, dig;
mp_get_buffer_raise(args[1], &pk, MP_BUFFER_READ);
mp_get_buffer_raise(args[2], &sig, MP_BUFFER_READ);
mp_get_buffer_raise(args[3], &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_VAR_BETWEEN(mod_TrezorCrypto_Secp256k1_verify_obj, 4, 4, mod_TrezorCrypto_Secp256k1_verify);
/// def trezor.crypto.curve.secp256k1.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 self, 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;
vstr_t vstr;
vstr_init_len(&vstr, 65);
if (0 == ecdsa_verify_digest_recover(&secp256k1, (uint8_t *)vstr.buf, (const uint8_t *)sig.buf + 1, (const uint8_t *)dig.buf, recid)) {
if (compressed) {
vstr.buf[0] = 0x02 | (vstr.buf[64] & 1);
vstr.len = 33;
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
} else {
return mp_const_none;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_TrezorCrypto_Secp256k1_verify_recover_obj, mod_TrezorCrypto_Secp256k1_verify_recover);
/// def trezor.crypto.curve.secp256k1.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 self, 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");
}
vstr_t vstr;
vstr_init_len(&vstr, 65);
if (0 != ecdh_multiply(&secp256k1, (const uint8_t *)sk.buf, (const uint8_t *)pk.buf, (uint8_t *)vstr.buf)) {
mp_raise_ValueError("Multiply failed");
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_TrezorCrypto_Secp256k1_multiply_obj, mod_TrezorCrypto_Secp256k1_multiply);
STATIC const mp_rom_map_elem_t mod_TrezorCrypto_Secp256k1_locals_dict_table[] = {
{ 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) },
};
STATIC MP_DEFINE_CONST_DICT(mod_TrezorCrypto_Secp256k1_locals_dict, mod_TrezorCrypto_Secp256k1_locals_dict_table);
STATIC const mp_obj_type_t mod_TrezorCrypto_Secp256k1_type = {
{ &mp_type_type },
.name = MP_QSTR_Secp256k1,
.make_new = mod_TrezorCrypto_Secp256k1_make_new,
.locals_dict = (void*)&mod_TrezorCrypto_Secp256k1_locals_dict,
};