1// Copyright (c) 2011 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include "crypto/hmac.h" 6 7#include <openssl/hmac.h> 8#include <stddef.h> 9 10#include <algorithm> 11#include <vector> 12 13#include "base/logging.h" 14#include "base/memory/scoped_ptr.h" 15#include "base/stl_util.h" 16#include "crypto/openssl_util.h" 17 18namespace crypto { 19 20struct HMACPlatformData { 21 std::vector<unsigned char> key; 22}; 23 24HMAC::HMAC(HashAlgorithm hash_alg) : hash_alg_(hash_alg) { 25 // Only SHA-1 and SHA-256 hash algorithms are supported now. 26 DCHECK(hash_alg_ == SHA1 || hash_alg_ == SHA256); 27} 28 29bool HMAC::Init(const unsigned char* key, size_t key_length) { 30 // Init must not be called more than once on the same HMAC object. 31 DCHECK(!plat_); 32 plat_.reset(new HMACPlatformData()); 33 plat_->key.assign(key, key + key_length); 34 return true; 35} 36 37HMAC::~HMAC() { 38 if (plat_) { 39 // Zero out key copy. 40 plat_->key.assign(plat_->key.size(), 0); 41 STLClearObject(&plat_->key); 42 } 43} 44 45bool HMAC::Sign(const base::StringPiece& data, 46 unsigned char* digest, 47 size_t digest_length) const { 48 DCHECK(plat_); // Init must be called before Sign. 49 50 ScopedOpenSSLSafeSizeBuffer<EVP_MAX_MD_SIZE> result(digest, digest_length); 51 return !!::HMAC(hash_alg_ == SHA1 ? EVP_sha1() : EVP_sha256(), 52 plat_->key.data(), plat_->key.size(), 53 reinterpret_cast<const unsigned char*>(data.data()), 54 data.size(), result.safe_buffer(), NULL); 55} 56 57} // namespace crypto 58