47 lines
1.6 KiB
C++
47 lines
1.6 KiB
C++
// Copyright (c) 2014 The Bitcoin Core 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 "crypto/rfc6979_hmac_sha256.h"
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#include <string.h>
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#include <algorithm>
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static const unsigned char zero[1] = {0x00};
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static const unsigned char one[1] = {0x01};
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RFC6979_HMAC_SHA256::RFC6979_HMAC_SHA256(const unsigned char* key, size_t keylen, const unsigned char* msg, size_t msglen) : retry(false)
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{
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memset(V, 0x01, sizeof(V));
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memset(K, 0x00, sizeof(K));
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CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Write(zero, sizeof(zero)).Write(key, keylen).Write(msg, msglen).Finalize(K);
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CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
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CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Write(one, sizeof(one)).Write(key, keylen).Write(msg, msglen).Finalize(K);
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CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
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}
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RFC6979_HMAC_SHA256::~RFC6979_HMAC_SHA256()
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{
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memset(V, 0x01, sizeof(V));
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memset(K, 0x00, sizeof(K));
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}
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void RFC6979_HMAC_SHA256::Generate(unsigned char* output, size_t outputlen)
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{
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if (retry) {
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CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Write(zero, sizeof(zero)).Finalize(K);
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CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
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}
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while (outputlen > 0) {
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CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
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size_t len = std::min(outputlen, sizeof(V));
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memcpy(output, V, len);
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output += len;
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outputlen -= len;
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}
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retry = true;
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}
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