90 lines
3.5 KiB
C
90 lines
3.5 KiB
C
/*
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* This file is part of the TREZOR project, https://trezor.io/
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*
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* Copyright (c) SatoshiLabs
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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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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