blob: 816bf60338119cd9314666cf241b6f3fd2944b56 [file] [log] [blame]
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Utility class for calculating the HMAC for a given message. We currently
// only support SHA1 for the hash algorithm, but this can be extended easily.
#ifndef CRYPTO_HMAC_H_
#define CRYPTO_HMAC_H_
#pragma once
#include <string>
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
namespace crypto {
// Simplify the interface and reduce includes by abstracting out the internals.
struct HMACPlatformData;
class HMAC {
public:
// The set of supported hash functions. Extend as required.
enum HashAlgorithm {
SHA1,
SHA256,
};
explicit HMAC(HashAlgorithm hash_alg);
~HMAC();
// Initializes this instance using |key| of the length |key_length|. Call Init
// only once. It returns false on the second or later calls.
bool Init(const unsigned char* key, int key_length);
// Initializes this instance using |key|. Call Init only once. It returns
// false on the second or later calls.
bool Init(const std::string& key) {
return Init(reinterpret_cast<const unsigned char*>(key.data()),
static_cast<int>(key.size()));
}
// Calculates the HMAC for the message in |data| using the algorithm supplied
// to the constructor and the key supplied to the Init method. The HMAC is
// returned in |digest|, which has |digest_length| bytes of storage available.
bool Sign(const std::string& data, unsigned char* digest, int digest_length);
// TODO(albertb): Add a Verify method.
private:
HashAlgorithm hash_alg_;
scoped_ptr<HMACPlatformData> plat_;
DISALLOW_COPY_AND_ASSIGN(HMAC);
};
} // namespace crypto
#endif // CRYPTO_HMAC_H_