mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-16 19:38:09 +00:00
78 lines
2.9 KiB
C
78 lines
2.9 KiB
C
/*
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* Copyright (c) Pavol Rusnak, SatoshiLabs
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*
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* Licensed under TREZOR License
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* see LICENSE file for details
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*/
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#include "py/objstr.h"
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#include "ed25519-donna/ed25519.h"
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#include "rand.h"
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/// def generate_secret() -> bytes:
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/// '''
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/// Generate secret key.
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/// '''
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STATIC mp_obj_t mod_trezorcrypto_curve25519_generate_secret() {
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uint8_t out[32];
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random_buffer(out, 32);
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// taken from https://cr.yp.to/ecdh.html
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out[0] &= 248;
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out[31] &= 127;
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out[31] |= 64;
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return mp_obj_new_bytes(out, sizeof(out));
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorcrypto_curve25519_generate_secret_obj, mod_trezorcrypto_curve25519_generate_secret);
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/// def publickey(secret_key: bytes) -> bytes:
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/// '''
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/// Computes public key from secret key.
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/// '''
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STATIC mp_obj_t mod_trezorcrypto_curve25519_publickey(mp_obj_t secret_key) {
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mp_buffer_info_t sk;
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mp_get_buffer_raise(secret_key, &sk, MP_BUFFER_READ);
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if (sk.len != 32) {
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mp_raise_ValueError("Invalid length of secret key");
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}
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uint8_t out[32];
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curve25519_scalarmult_basepoint(out, (const uint8_t *)sk.buf);
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return mp_obj_new_bytes(out, sizeof(out));
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_curve25519_publickey_obj, mod_trezorcrypto_curve25519_publickey);
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/// def multiply(secret_key: bytes, public_key: bytes) -> bytes:
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/// '''
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/// Multiplies point defined by public_key with scalar defined by secret_key.
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/// Useful for ECDH.
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/// '''
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STATIC mp_obj_t mod_trezorcrypto_curve25519_multiply(mp_obj_t secret_key, mp_obj_t public_key) {
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mp_buffer_info_t sk, pk;
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mp_get_buffer_raise(secret_key, &sk, MP_BUFFER_READ);
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mp_get_buffer_raise(public_key, &pk, MP_BUFFER_READ);
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if (sk.len != 32) {
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mp_raise_ValueError("Invalid length of secret key");
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}
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if (pk.len != 32) {
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mp_raise_ValueError("Invalid length of public key");
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}
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uint8_t out[32];
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curve25519_scalarmult(out, (const uint8_t *)sk.buf, (const uint8_t *)pk.buf);
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return mp_obj_new_bytes(out, sizeof(out));
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_curve25519_multiply_obj, mod_trezorcrypto_curve25519_multiply);
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STATIC const mp_rom_map_elem_t mod_trezorcrypto_curve25519_globals_table[] = {
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{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_curve25519) },
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{ MP_ROM_QSTR(MP_QSTR_generate_secret), MP_ROM_PTR(&mod_trezorcrypto_curve25519_generate_secret_obj) },
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{ MP_ROM_QSTR(MP_QSTR_publickey), MP_ROM_PTR(&mod_trezorcrypto_curve25519_publickey_obj) },
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{ MP_ROM_QSTR(MP_QSTR_multiply), MP_ROM_PTR(&mod_trezorcrypto_curve25519_multiply_obj) },
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};
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STATIC MP_DEFINE_CONST_DICT(mod_trezorcrypto_curve25519_globals, mod_trezorcrypto_curve25519_globals_table);
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STATIC const mp_obj_module_t mod_trezorcrypto_curve25519_module = {
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.base = { &mp_type_module },
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.globals = (mp_obj_dict_t*)&mod_trezorcrypto_curve25519_globals,
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};
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