68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2014 The Bitcoin developers
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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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#include "eccryptoverify.h"
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namespace {
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int CompareBigEndian(const unsigned char *c1, size_t c1len, const unsigned char *c2, size_t c2len) {
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while (c1len > c2len) {
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if (*c1)
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return 1;
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c1++;
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c1len--;
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}
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while (c2len > c1len) {
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if (*c2)
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return -1;
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c2++;
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c2len--;
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}
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while (c1len > 0) {
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if (*c1 > *c2)
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return 1;
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if (*c2 > *c1)
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return -1;
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c1++;
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c2++;
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c1len--;
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}
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return 0;
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}
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/** Order of secp256k1's generator minus 1. */
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const unsigned char vchMaxModOrder[32] = {
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFE,
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0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,
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0xBF,0xD2,0x5E,0x8C,0xD0,0x36,0x41,0x40
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};
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/** Half of the order of secp256k1's generator minus 1. */
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const unsigned char vchMaxModHalfOrder[32] = {
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0x7F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0x5D,0x57,0x6E,0x73,0x57,0xA4,0x50,0x1D,
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0xDF,0xE9,0x2F,0x46,0x68,0x1B,0x20,0xA0
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};
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const unsigned char vchZero[1] = {0};
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} // anon namespace
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namespace eccrypto {
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bool Check(const unsigned char *vch) {
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return vch &&
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CompareBigEndian(vch, 32, vchZero, 0) > 0 &&
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CompareBigEndian(vch, 32, vchMaxModOrder, 32) <= 0;
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}
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bool CheckSignatureElement(const unsigned char *vch, int len, bool half) {
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return vch &&
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CompareBigEndian(vch, len, vchZero, 0) > 0 &&
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CompareBigEndian(vch, len, half ? vchMaxModHalfOrder : vchMaxModOrder, 32) <= 0;
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}
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} // namespace eccrypto
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