100 lines
3.1 KiB
C
100 lines
3.1 KiB
C
/**********************************************************************
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* Copyright (c) 2013, 2014 Pieter Wuille *
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* Distributed under the MIT software license, see the accompanying *
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* file COPYING or http://www.opensource.org/licenses/mit-license.php.*
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**********************************************************************/
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#ifndef _SECP256K1_ECKEY_IMPL_H_
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#define _SECP256K1_ECKEY_IMPL_H_
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#include "eckey.h"
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#include "scalar.h"
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#include "field.h"
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#include "group.h"
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#include "ecmult_gen.h"
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static int secp256k1_eckey_pubkey_parse(secp256k1_ge *elem, const unsigned char *pub, size_t size) {
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if (size == 33 && (pub[0] == 0x02 || pub[0] == 0x03)) {
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secp256k1_fe x;
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return secp256k1_fe_set_b32(&x, pub+1) && secp256k1_ge_set_xo_var(elem, &x, pub[0] == 0x03);
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} else if (size == 65 && (pub[0] == 0x04 || pub[0] == 0x06 || pub[0] == 0x07)) {
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secp256k1_fe x, y;
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if (!secp256k1_fe_set_b32(&x, pub+1) || !secp256k1_fe_set_b32(&y, pub+33)) {
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return 0;
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}
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secp256k1_ge_set_xy(elem, &x, &y);
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if ((pub[0] == 0x06 || pub[0] == 0x07) && secp256k1_fe_is_odd(&y) != (pub[0] == 0x07)) {
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return 0;
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}
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return secp256k1_ge_is_valid_var(elem);
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} else {
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return 0;
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}
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}
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static int secp256k1_eckey_pubkey_serialize(secp256k1_ge *elem, unsigned char *pub, size_t *size, int compressed) {
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if (secp256k1_ge_is_infinity(elem)) {
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return 0;
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}
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secp256k1_fe_normalize_var(&elem->x);
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secp256k1_fe_normalize_var(&elem->y);
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secp256k1_fe_get_b32(&pub[1], &elem->x);
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if (compressed) {
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*size = 33;
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pub[0] = 0x02 | (secp256k1_fe_is_odd(&elem->y) ? 0x01 : 0x00);
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} else {
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*size = 65;
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pub[0] = 0x04;
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secp256k1_fe_get_b32(&pub[33], &elem->y);
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}
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return 1;
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}
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static int secp256k1_eckey_privkey_tweak_add(secp256k1_scalar *key, const secp256k1_scalar *tweak) {
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secp256k1_scalar_add(key, key, tweak);
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if (secp256k1_scalar_is_zero(key)) {
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return 0;
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}
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return 1;
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}
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static int secp256k1_eckey_pubkey_tweak_add(const secp256k1_ecmult_context *ctx, secp256k1_ge *key, const secp256k1_scalar *tweak) {
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secp256k1_gej pt;
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secp256k1_scalar one;
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secp256k1_gej_set_ge(&pt, key);
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secp256k1_scalar_set_int(&one, 1);
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secp256k1_ecmult(ctx, &pt, &pt, &one, tweak);
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if (secp256k1_gej_is_infinity(&pt)) {
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return 0;
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}
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secp256k1_ge_set_gej(key, &pt);
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return 1;
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}
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static int secp256k1_eckey_privkey_tweak_mul(secp256k1_scalar *key, const secp256k1_scalar *tweak) {
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if (secp256k1_scalar_is_zero(tweak)) {
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return 0;
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}
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secp256k1_scalar_mul(key, key, tweak);
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return 1;
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}
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static int secp256k1_eckey_pubkey_tweak_mul(const secp256k1_ecmult_context *ctx, secp256k1_ge *key, const secp256k1_scalar *tweak) {
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secp256k1_scalar zero;
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secp256k1_gej pt;
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if (secp256k1_scalar_is_zero(tweak)) {
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return 0;
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}
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secp256k1_scalar_set_int(&zero, 0);
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secp256k1_gej_set_ge(&pt, key);
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secp256k1_ecmult(ctx, &pt, &pt, tweak, &zero);
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secp256k1_ge_set_gej(key, &pt);
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return 1;
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}
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#endif
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