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core/secp256k1_zkp: refactor API into a Context class

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In order to prevent frequent memory allocations, the user can create a single
Context object and re-use it between subsequent cryptographic operations.
This commit is contained in:
Roman Zeyde 2019-05-28 11:46:14 +03:00 committed by Pavol Rusnak
parent 91b23f3ea2
commit b538eb3375
No known key found for this signature in database
GPG Key ID: 91F3B339B9A02A3D
3 changed files with 213 additions and 141 deletions
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273
core/embed/extmod/modtrezorcrypto/modtrezorcrypto-secp256k1_zkp.h
View File

@ -37,79 +37,115 @@ void secp256k1_default_error_callback_fn(const char *str, void *data) {
return;
}
static secp256k1_context *secp256k1_ctx = NULL;
static void *secp256k1_ctx_buf = NULL;
static size_t secp256k1_ctx_size = 0;
static const secp256k1_context *mod_trezorcrypto_secp256k1_context_create(
void) {
if (secp256k1_ctx == NULL) {
secp256k1_ctx_size = secp256k1_context_preallocated_size(
SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
secp256k1_ctx_buf = m_new_maybe(uint8_t, secp256k1_ctx_size);
if (!secp256k1_ctx_buf) {
mp_raise_ValueError("secp256k1_zkp context is too large");
}
secp256k1_ctx = secp256k1_context_preallocated_create(
secp256k1_ctx_buf, SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
uint8_t rand[32];
random_buffer(rand, 32);
int ret = secp256k1_context_randomize(secp256k1_ctx, rand);
if (ret != 1) {
mp_raise_msg(&mp_type_RuntimeError, "secp256k1_context_randomize failed");
}
}
return secp256k1_ctx;
}
STATIC void mod_trezorcrypto_secp256k1_context_delete(void) {
secp256k1_context_preallocated_destroy(secp256k1_ctx);
m_del(uint8_t, secp256k1_ctx_buf, secp256k1_ctx_size);
secp256k1_ctx_buf = NULL;
secp256k1_ctx = NULL;
}
/// package: trezorcrypto.secp256k1_zkp
/// def generate_secret() -> bytes:
/// class Context:
/// """
/// Owns a secp256k1 context.
/// Can be allocated once and re-used between subsequent operations.
/// """
///
typedef struct _mp_obj_secp256k1_context_t {
mp_obj_base_t base;
secp256k1_context *secp256k1_ctx;
size_t secp256k1_ctx_size;
uint8_t secp256k1_ctx_buf[0]; // to be allocate via m_new_obj_var_maybe().
} mp_obj_secp256k1_context_t;
/// def __init__(self):
/// """
/// Allocate and initialize secp256k1_context.
/// """
STATIC mp_obj_t mod_trezorcrypto_secp256k1_context_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);
const size_t secp256k1_ctx_size = secp256k1_context_preallocated_size(
SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
mp_obj_secp256k1_context_t *o = m_new_obj_var_maybe(
mp_obj_secp256k1_context_t, uint8_t, secp256k1_ctx_size);
if (!o) {
mp_raise_ValueError("secp256k1_zkp context is too large");
}
o->base.type = type;
o->secp256k1_ctx_size = secp256k1_ctx_size;
o->secp256k1_ctx = secp256k1_context_preallocated_create(
o->secp256k1_ctx_buf, SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
uint8_t rand[32] = {0};
random_buffer(rand, 32);
int ret = secp256k1_context_randomize(o->secp256k1_ctx, rand);
if (ret != 1) {
mp_raise_msg(&mp_type_RuntimeError, "secp256k1_context_randomize failed");
}
return MP_OBJ_FROM_PTR(o);
}
/// def __del__(self):
/// """
/// Destructor.
/// """
STATIC mp_obj_t mod_trezorcrypto_secp256k1_context___del__(mp_obj_t self) {
mp_obj_secp256k1_context_t *o = MP_OBJ_TO_PTR(self);
secp256k1_context_preallocated_destroy(o->secp256k1_ctx);
memzero(o->secp256k1_ctx_buf, o->secp256k1_ctx_size);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_secp256k1_context___del___obj,
mod_trezorcrypto_secp256k1_context___del__);
/// def size(self):
/// """
/// Return the size in bytes of the internal secp256k1_ctx_buf buffer.
/// """
STATIC mp_obj_t mod_trezorcrypto_secp256k1_context_size(mp_obj_t self) {
mp_obj_secp256k1_context_t *o = MP_OBJ_TO_PTR(self);
return mp_obj_new_int_from_uint(o->secp256k1_ctx_size);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_secp256k1_context_size_obj,
mod_trezorcrypto_secp256k1_context_size);
static const secp256k1_context *mod_trezorcrypto_get_secp256k1_context(
mp_obj_t self) {
mp_obj_secp256k1_context_t *o = MP_OBJ_TO_PTR(self);
return o->secp256k1_ctx;
}
/// def generate_secret(self) -> bytes:
/// """
/// Generate secret key.
/// """
STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_generate_secret() {
uint8_t out[32];
STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_generate_secret(mp_obj_t self) {
const secp256k1_context *ctx = mod_trezorcrypto_get_secp256k1_context(self);
uint8_t out[32] = {0};
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;
if (secp256k1_ec_seckey_verify(ctx, out) == 1) {
break;
}
}
return mp_obj_new_bytes(out, sizeof(out));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_0(
STATIC MP_DEFINE_CONST_FUN_OBJ_1(
mod_trezorcrypto_secp256k1_zkp_generate_secret_obj,
mod_trezorcrypto_secp256k1_zkp_generate_secret);
/// def publickey(secret_key: bytes, compressed: bool = True) -> bytes:
/// def publickey(self, secret_key: bytes, compressed: bool = True) -> bytes:
/// """
/// Computes public key from secret key.
/// """
STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_publickey(size_t n_args,
const mp_obj_t *args) {
const secp256k1_context *ctx = mod_trezorcrypto_secp256k1_context_create();
STATIC mp_obj_t mod_trezorcrypto_secp256k1_context_publickey(
size_t n_args, const mp_obj_t *args) {
const secp256k1_context *ctx =
mod_trezorcrypto_get_secp256k1_context(args[0]);
mp_buffer_info_t sk;
mp_get_buffer_raise(args[0], &sk, MP_BUFFER_READ);
mp_get_buffer_raise(args[1], &sk, MP_BUFFER_READ);
secp256k1_pubkey pk;
if (sk.len != 32) {
mp_raise_ValueError("Invalid length of secret key");
@ -118,32 +154,32 @@ STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_publickey(size_t n_args,
mp_raise_ValueError("Invalid secret key");
}
bool compressed = n_args < 2 || args[1] == mp_const_true;
bool compressed = n_args < 3 || args[2] == mp_const_true;
uint8_t out[65];
size_t outlen = sizeof(out);
secp256k1_ec_pubkey_serialize(
ctx, out, &outlen, &pk,
compressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
mod_trezorcrypto_secp256k1_context_delete();
return mp_obj_new_bytes(out, outlen);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(
mod_trezorcrypto_secp256k1_zkp_publickey_obj, 1, 2,
mod_trezorcrypto_secp256k1_zkp_publickey);
mod_trezorcrypto_secp256k1_context_publickey_obj, 2, 3,
mod_trezorcrypto_secp256k1_context_publickey);
/// def sign(
/// secret_key: bytes, digest: bytes, compressed: bool = True
/// self, 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_zkp_sign(size_t n_args,
const mp_obj_t *args) {
const secp256k1_context *ctx = mod_trezorcrypto_secp256k1_context_create();
STATIC mp_obj_t mod_trezorcrypto_secp256k1_context_sign(size_t n_args,
const mp_obj_t *args) {
const secp256k1_context *ctx =
mod_trezorcrypto_get_secp256k1_context(args[0]);
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_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");
}
@ -159,27 +195,28 @@ STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_sign(size_t n_args,
}
secp256k1_ecdsa_recoverable_signature_serialize_compact(ctx, &out[1], &pby,
&sig);
mod_trezorcrypto_secp256k1_context_delete();
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_zkp_sign_obj, 2, 3,
mod_trezorcrypto_secp256k1_zkp_sign);
mod_trezorcrypto_secp256k1_context_sign_obj, 3, 4,
mod_trezorcrypto_secp256k1_context_sign);
/// def verify(public_key: bytes, signature: bytes, digest: bytes) -> bool:
/// def verify(
/// self, 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_zkp_verify(mp_obj_t public_key,
mp_obj_t signature,
mp_obj_t digest) {
const secp256k1_context *ctx = mod_trezorcrypto_secp256k1_context_create();
STATIC mp_obj_t
mod_trezorcrypto_secp256k1_context_verify(size_t n_args, const mp_obj_t *args) {
const secp256k1_context *ctx =
mod_trezorcrypto_get_secp256k1_context(args[0]);
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);
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) {
return mp_const_false;
}
@ -202,20 +239,20 @@ STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_verify(mp_obj_t public_key,
}
bool ret = (1 == secp256k1_ecdsa_verify(ctx, &ec_sig,
(const uint8_t *)dig.buf, &ec_pk));
mod_trezorcrypto_secp256k1_context_delete();
return mp_obj_new_bool(ret);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_trezorcrypto_secp256k1_zkp_verify_obj,
mod_trezorcrypto_secp256k1_zkp_verify);
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(
mod_trezorcrypto_secp256k1_context_verify_obj, 4, 4,
mod_trezorcrypto_secp256k1_context_verify);
/// def verify_recover(signature: bytes, digest: bytes) -> bytes:
/// def verify_recover(self, 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 if the signature is invalid.
/// """
STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_verify_recover(
mp_obj_t signature, mp_obj_t digest) {
const secp256k1_context *ctx = mod_trezorcrypto_secp256k1_context_create();
STATIC mp_obj_t mod_trezorcrypto_secp256k1_context_verify_recover(
mp_obj_t self, mp_obj_t signature, mp_obj_t digest) {
const secp256k1_context *ctx = mod_trezorcrypto_get_secp256k1_context(self);
mp_buffer_info_t sig, dig;
mp_get_buffer_raise(signature, &sig, MP_BUFFER_READ);
mp_get_buffer_raise(digest, &dig, MP_BUFFER_READ);
@ -246,12 +283,11 @@ STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_verify_recover(
secp256k1_ec_pubkey_serialize(
ctx, out, &pklen, &pk,
compressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
mod_trezorcrypto_secp256k1_context_delete();
return mp_obj_new_bytes(out, pklen);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(
mod_trezorcrypto_secp256k1_zkp_verify_recover_obj,
mod_trezorcrypto_secp256k1_zkp_verify_recover);
STATIC MP_DEFINE_CONST_FUN_OBJ_3(
mod_trezorcrypto_secp256k1_context_verify_recover_obj,
mod_trezorcrypto_secp256k1_context_verify_recover);
static int secp256k1_ecdh_hash_passthrough(uint8_t *output, const uint8_t *x,
const uint8_t *y, void *data) {
@ -262,14 +298,14 @@ static int secp256k1_ecdh_hash_passthrough(uint8_t *output, const uint8_t *x,
return 1;
}
/// def multiply(secret_key: bytes, public_key: bytes) -> bytes:
/// def multiply(self, 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_zkp_multiply(mp_obj_t secret_key,
mp_obj_t public_key) {
const secp256k1_context *ctx = mod_trezorcrypto_secp256k1_context_create();
STATIC mp_obj_t mod_trezorcrypto_secp256k1_context_multiply(
mp_obj_t self, mp_obj_t secret_key, mp_obj_t public_key) {
const secp256k1_context *ctx = mod_trezorcrypto_get_secp256k1_context(self);
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);
@ -289,27 +325,50 @@ STATIC mp_obj_t mod_trezorcrypto_secp256k1_zkp_multiply(mp_obj_t secret_key,
secp256k1_ecdh_hash_passthrough, NULL)) {
mp_raise_ValueError("Multiply failed");
}
mod_trezorcrypto_secp256k1_context_delete();
return mp_obj_new_bytes(out, sizeof(out));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_secp256k1_zkp_multiply_obj,
mod_trezorcrypto_secp256k1_zkp_multiply);
STATIC MP_DEFINE_CONST_FUN_OBJ_3(
mod_trezorcrypto_secp256k1_context_multiply_obj,
mod_trezorcrypto_secp256k1_context_multiply);
//////////////////////////////////////////////////////////////////////////////
STATIC const mp_rom_map_elem_t
mod_trezorcrypto_secp256k1_context_locals_dict_table[] = {
{MP_ROM_QSTR(MP_QSTR___del__),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context___del___obj)},
{MP_ROM_QSTR(MP_QSTR_size),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context_size_obj)},
{MP_ROM_QSTR(MP_QSTR_generate_secret),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_zkp_generate_secret_obj)},
{MP_ROM_QSTR(MP_QSTR_publickey),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context_publickey_obj)},
{MP_ROM_QSTR(MP_QSTR_sign),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context_sign_obj)},
{MP_ROM_QSTR(MP_QSTR_verify),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context_verify_obj)},
{MP_ROM_QSTR(MP_QSTR_verify_recover),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context_verify_recover_obj)},
{MP_ROM_QSTR(MP_QSTR_multiply),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context_multiply_obj)},
};
STATIC MP_DEFINE_CONST_DICT(
mod_trezorcrypto_secp256k1_context_locals_dict,
mod_trezorcrypto_secp256k1_context_locals_dict_table);
STATIC const mp_obj_type_t mod_trezorcrypto_secp256k1_context_type = {
{&mp_type_type},
.name = MP_QSTR_Context,
.make_new = mod_trezorcrypto_secp256k1_context_make_new,
.locals_dict = (void *)&mod_trezorcrypto_secp256k1_context_locals_dict,
};
STATIC const mp_rom_map_elem_t
mod_trezorcrypto_secp256k1_zkp_globals_table[] = {
{MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_secp256k1_zkp)},
{MP_ROM_QSTR(MP_QSTR_generate_secret),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_zkp_generate_secret_obj)},
{MP_ROM_QSTR(MP_QSTR_publickey),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_zkp_publickey_obj)},
{MP_ROM_QSTR(MP_QSTR_sign),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_zkp_sign_obj)},
{MP_ROM_QSTR(MP_QSTR_verify),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_zkp_verify_obj)},
{MP_ROM_QSTR(MP_QSTR_verify_recover),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_zkp_verify_recover_obj)},
{MP_ROM_QSTR(MP_QSTR_multiply),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_zkp_multiply_obj)},
{MP_ROM_QSTR(MP_QSTR_Context),
MP_ROM_PTR(&mod_trezorcrypto_secp256k1_context_type)},
};
STATIC MP_DEFINE_CONST_DICT(mod_trezorcrypto_secp256k1_zkp_globals,
mod_trezorcrypto_secp256k1_zkp_globals_table);

79
core/mocks/generated/trezorcrypto/secp256k1_zkp.py
View File

@ -2,47 +2,60 @@ from typing import *
# extmod/modtrezorcrypto/modtrezorcrypto-secp256k1_zkp.h
def generate_secret() -> bytes:
class Context:
"""
Generate secret key.
Owns a secp256k1 context.
Can be allocated once and re-used between subsequent operations.
"""
def __init__(self):
"""
Allocate and initialize secp256k1_context.
"""
# extmod/modtrezorcrypto/modtrezorcrypto-secp256k1_zkp.h
def publickey(secret_key: bytes, compressed: bool = True) -> bytes:
"""
Computes public key from secret key.
"""
def __del__(self):
"""
Destructor.
"""
def size(self):
"""
Return the size in bytes of the internal secp256k1_ctx_buf buffer.
"""
# extmod/modtrezorcrypto/modtrezorcrypto-secp256k1_zkp.h
def sign(
secret_key: bytes, digest: bytes, compressed: bool = True
) -> bytes:
"""
Uses secret key to produce the signature of the digest.
"""
def generate_secret(self) -> bytes:
"""
Generate secret key.
"""
def publickey(self, secret_key: bytes, compressed: bool = True) -> bytes:
"""
Computes public key from secret key.
"""
# extmod/modtrezorcrypto/modtrezorcrypto-secp256k1_zkp.h
def verify(public_key: bytes, signature: bytes, digest: bytes) -> bool:
"""
Uses public key to verify the signature of the digest.
Returns True on success.
"""
def sign(
self, secret_key: bytes, digest: bytes, compressed: bool = True
) -> bytes:
"""
Uses secret key to produce the signature of the digest.
"""
def verify(
self, public_key: bytes, signature: bytes, digest: bytes
) -> bool:
"""
Uses public key to verify the signature of the digest.
Returns True on success.
"""
# extmod/modtrezorcrypto/modtrezorcrypto-secp256k1_zkp.h
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 if the signature is invalid.
"""
def verify_recover(self, 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 if the signature is invalid.
"""
# extmod/modtrezorcrypto/modtrezorcrypto-secp256k1_zkp.h
def multiply(secret_key: bytes, public_key: bytes) -> bytes:
"""
Multiplies point defined by public_key with scalar defined by
secret_key. Useful for ECDH.
"""
def multiply(self, secret_key: bytes, public_key: bytes) -> bytes:
"""
Multiplies point defined by public_key with scalar defined by
secret_key. Useful for ECDH.
"""

2
core/tests/test_trezor.crypto.curve.secp256k1.py
View File

@ -139,7 +139,7 @@ class TestCryptoSecp256k1(Secp256k1Common, unittest.TestCase):
class TestCryptoSecp256k1Zkp(Secp256k1Common, unittest.TestCase):
def __init__(self):
self.impl = secp256k1_zkp
self.impl = secp256k1_zkp.Context()
if __name__ == '__main__':
unittest.main()