mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-29 17:48:10 +00:00
109 lines
3.6 KiB
C
109 lines
3.6 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 "trezor-crypto/bignum.h"
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#include "ssss.h"
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/// class SSSS:
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/// '''
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/// '''
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typedef struct _mp_obj_SSSS_t {
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mp_obj_base_t base;
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} mp_obj_SSSS_t;
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/// def __init__(self) -> None:
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/// '''
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/// '''
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STATIC mp_obj_t mod_trezorcrypto_SSSS_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
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mp_arg_check_num(n_args, n_kw, 0, 0, false);
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mp_obj_SSSS_t *o = m_new_obj(mp_obj_SSSS_t);
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o->base.type = type;
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return MP_OBJ_FROM_PTR(o);
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}
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/// def split(self, m: int, n: int, secret: bytes) -> tuple:
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/// '''
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/// Split secret to (M of N) shares using Shamir's Secret Sharing Scheme.
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/// '''
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STATIC mp_obj_t mod_trezorcrypto_SSSS_split(size_t n_args, const mp_obj_t *args) {
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mp_int_t m = mp_obj_get_int(args[1]);
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mp_int_t n = mp_obj_get_int(args[2]);
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mp_buffer_info_t secret;
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mp_get_buffer_raise(args[3], &secret, MP_BUFFER_READ);
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if (secret.len != 32) {
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mp_raise_ValueError("Length of the secret has to be 256 bits");
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}
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if (m < 1 || n < 1 || m > 15 || n > 15 || m > n) {
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mp_raise_ValueError("Invalid number of shares");
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}
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bignum256 sk;
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bignum256 shares[n];
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bn_read_be(secret.buf, &sk);
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if (!ssss_split(&sk, m, n, shares)) {
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mp_raise_ValueError("Error splitting secret");
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}
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mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(mp_obj_new_tuple(n, NULL));
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vstr_t vstr[n];
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for (int i = 0; i < n; i++) {
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vstr_init_len(&vstr[i], secret.len);
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bn_write_be(&shares[i], secret.buf);
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tuple->items[i] = mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr[i]);
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}
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return MP_OBJ_FROM_PTR(tuple);
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorcrypto_SSSS_split_obj, 4, 4, mod_trezorcrypto_SSSS_split);
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/// def combine(self, shares: tuple) -> bytes:
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/// '''
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/// Combine M shares of Shamir's Secret Sharing Scheme into secret.
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/// '''
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STATIC mp_obj_t mod_trezorcrypto_SSSS_combine(mp_obj_t self, mp_obj_t shares) {
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size_t n;
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mp_obj_t *share;
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mp_obj_get_array(shares, &n, &share);
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if (n < 1 || n > 15) {
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mp_raise_ValueError("Invalid number of shares");
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}
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bignum256 bnshares[n];
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for (size_t i = 0; i < n; i++) {
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if (MP_OBJ_IS_TYPE(share[i], &mp_type_bytes)) {
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mp_buffer_info_t s;
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mp_get_buffer_raise(share[i], &s, MP_BUFFER_READ);
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if (s.len != 32) {
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mp_raise_ValueError("Length of share has to be 256 bits");
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}
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bn_read_be(s.buf, &bnshares[n]);
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} else {
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memset(&bnshares[i], 0, sizeof(bignum256));
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}
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}
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bignum256 sk;
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if (!ssss_combine(bnshares, n, &sk)) {
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mp_raise_ValueError("Error combining secret");
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}
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vstr_t vstr;
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vstr_init_len(&vstr, 32);
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bn_write_be(&sk, (uint8_t *)vstr.buf);
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return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_SSSS_combine_obj, mod_trezorcrypto_SSSS_combine);
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STATIC const mp_rom_map_elem_t mod_trezorcrypto_SSSS_locals_dict_table[] = {
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{ MP_ROM_QSTR(MP_QSTR_split), MP_ROM_PTR(&mod_trezorcrypto_SSSS_split_obj) },
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{ MP_ROM_QSTR(MP_QSTR_combine), MP_ROM_PTR(&mod_trezorcrypto_SSSS_combine_obj) },
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};
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STATIC MP_DEFINE_CONST_DICT(mod_trezorcrypto_SSSS_locals_dict, mod_trezorcrypto_SSSS_locals_dict_table);
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STATIC const mp_obj_type_t mod_trezorcrypto_SSSS_type = {
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{ &mp_type_type },
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.name = MP_QSTR_SSSS,
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.make_new = mod_trezorcrypto_SSSS_make_new,
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.locals_dict = (void*)&mod_trezorcrypto_SSSS_locals_dict,
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};
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