Pieter Wuille
10 years ago
4 changed files with 121 additions and 0 deletions
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// Copyright (c) 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 "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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// Copyright (c) 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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#ifndef BITCOIN_RFC6979_HMAC_SHA256_H |
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#define BITCOIN_RFC6979_HMAC_SHA256_H |
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#include "crypto/hmac_sha256.h" |
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#include <stdint.h> |
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#include <stdlib.h> |
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/** The RFC 6979 PRNG using HMAC-SHA256. */ |
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class RFC6979_HMAC_SHA256 |
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{ |
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private: |
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unsigned char V[CHMAC_SHA256::OUTPUT_SIZE]; |
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unsigned char K[CHMAC_SHA256::OUTPUT_SIZE]; |
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bool retry; |
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public: |
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/**
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* Construct a new RFC6979 PRNG, using the given key and message. |
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* The message is assumed to be already hashed. |
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*/ |
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RFC6979_HMAC_SHA256(const unsigned char* key, size_t keylen, const unsigned char* msg, size_t msglen); |
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/**
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* Generate a byte array. |
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*/ |
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void Generate(unsigned char* output, size_t outputlen); |
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~RFC6979_HMAC_SHA256(); |
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}; |
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#endif // BITCOIN_RFC6979_HMAC_SHA256_H
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