base/hmac.h

// Copyright (c) 2006-2008 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 BASE_HMAC_H_
#define BASE_HMAC_H_

#include <string>

#include "base/basictypes.h"
#include "base/scoped_ptr.h"

namespace base {

// 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
  };

  HMAC(HashAlgorithm hash_alg, const unsigned char* key, int key_length);
  ~HMAC();

  // Calculates the HMAC for the message in |data| using the algorithm and key
  // supplied to the constructor.  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);

 private:
  HashAlgorithm hash_alg_;
  scoped_ptr<HMACPlatformData> plat_;

  DISALLOW_COPY_AND_ASSIGN(HMAC);
};

}  // namespace base

#endif  // BASE_HMAC_H_