add trezor.crypto.ssss skeleton

extmod/modtrezorcrypto/modtrezorcrypto-ssss.h

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) Pavol Rusnak, SatoshiLabs
+ *
+ * Licensed under TREZOR License
+ * see LICENSE file for details
+ */
+
+#include "py/objstr.h"
+
+typedef struct _mp_obj_SSSS_t {
+    mp_obj_base_t base;
+} mp_obj_SSSS_t;
+
+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) {
+    mp_arg_check_num(n_args, n_kw, 0, 0, false);
+    mp_obj_SSSS_t *o = m_new_obj(mp_obj_SSSS_t);
+    o->base.type = type;
+    return MP_OBJ_FROM_PTR(o);
+}
+
+/// def trezor.crypto.ssss.split(m: int, n: int, secret: bytes) -> tuple
+///
+/// Split secret to (M of N) shares using Shamir's Secret Sharing Scheme
+///
+STATIC mp_obj_t mod_TrezorCrypto_SSSS_split(size_t n_args, const mp_obj_t *args) {
+    mp_int_t m = mp_obj_get_int(args[1]);
+    mp_int_t n = mp_obj_get_int(args[2]);
+    mp_buffer_info_t secret;
+    mp_get_buffer_raise(args[3], &secret, MP_BUFFER_READ);
+    (void)m;
+    mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(mp_obj_new_tuple(n, NULL));
+    vstr_t vstr[n];
+    for (int i = 0; i < n; i++) {
+        vstr_init_len(&vstr[i], secret.len);
+        memcpy(vstr[i].buf, secret.buf, secret.len);
+        tuple->items[i] = mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr[i]);
+    }
+    return MP_OBJ_FROM_PTR(tuple);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_TrezorCrypto_SSSS_split_obj, 4, 4, mod_TrezorCrypto_SSSS_split);
+
+/// def trezor.crypto.ssss.combine(shares: tuple) -> bytes
+///
+/// Combine M shares of Shamir's Secret Sharing Scheme into secret
+///
+STATIC mp_obj_t mod_TrezorCrypto_SSSS_combine(mp_obj_t self, mp_obj_t shares) {
+    mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(shares);
+    mp_int_t m = 0;
+    mp_int_t n = tuple->len;
+    for (int i = 0; i < n; i++) {
+        mp_obj_t share = tuple->items[i];
+        if (share != mp_const_none) {
+            m++;
+        }
+    }
+    return tuple->items[0];
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_TrezorCrypto_SSSS_combine_obj, mod_TrezorCrypto_SSSS_combine);
+
+STATIC const mp_rom_map_elem_t mod_TrezorCrypto_SSSS_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_split), MP_ROM_PTR(&mod_TrezorCrypto_SSSS_split_obj) },
+    { MP_ROM_QSTR(MP_QSTR_combine), MP_ROM_PTR(&mod_TrezorCrypto_SSSS_combine_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(mod_TrezorCrypto_SSSS_locals_dict, mod_TrezorCrypto_SSSS_locals_dict_table);
+
+STATIC const mp_obj_type_t mod_TrezorCrypto_SSSS_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_SSSS,
+    .make_new = mod_TrezorCrypto_SSSS_make_new,
+    .locals_dict = (void*)&mod_TrezorCrypto_SSSS_locals_dict,
+};

extmod/modtrezorcrypto/modtrezorcrypto.c

@@ -25,6 +25,7 @@
 #include "modtrezorcrypto-sha512.h"
 #include "modtrezorcrypto-sha3-256.h"
 #include "modtrezorcrypto-sha3-512.h"
+#include "modtrezorcrypto-ssss.h"
 
 STATIC const mp_rom_map_elem_t mp_module_TrezorCrypto_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_TrezorCrypto) },
@@ -38,6 +39,7 @@ STATIC const mp_rom_map_elem_t mp_module_TrezorCrypto_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_Sha512), MP_ROM_PTR(&mod_TrezorCrypto_Sha512_type) },
     { MP_ROM_QSTR(MP_QSTR_Sha3_256), MP_ROM_PTR(&mod_TrezorCrypto_Sha3_256_type) },
     { MP_ROM_QSTR(MP_QSTR_Sha3_512), MP_ROM_PTR(&mod_TrezorCrypto_Sha3_512_type) },
+    { MP_ROM_QSTR(MP_QSTR_SSSS), MP_ROM_PTR(&mod_TrezorCrypto_SSSS_type) },
 };
 STATIC MP_DEFINE_CONST_DICT(mp_module_TrezorCrypto_globals, mp_module_TrezorCrypto_globals_table);
 

src/trezor/crypto/__init__.py

@@ -1,4 +1,6 @@
 from TrezorCrypto import Pbkdf2 as pbkdf2
 from TrezorCrypto import Bip39
+from TrezorCrypto import SSSS
 
 bip39 = Bip39()
+ssss = SSSS()