source: XMLIO_V2/external/src/POCO/Foundation.save/Poco/HMACEngine.h @ 80

//
// HMACEngine.h
//
// $Id: //poco/1.3/Foundation/include/Poco/HMACEngine.h#3 $
//
// Library: Foundation
// Package: Crypt
// Module:  HMACEngine
//
// Definition of the HMACEngine class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Foundation_HMACEngine_INCLUDED
#define Foundation_HMACEngine_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/DigestEngine.h"
#include <cstring>


namespace Poco {


template <class Engine>
class HMACEngine: public DigestEngine
        /// This class implementes the HMAC message
        /// authentication code algorithm, as specified
        /// in RFC 2104. The underlying DigestEngine
        /// (MD5Engine, SHA1Engine, etc.) must be given as 
        /// template argument.
        /// Since the HMACEngine is a DigestEngine, it can
        /// be used with the DigestStream class to create
        /// a HMAC for a stream.
{
public:
        enum
        {
                BLOCK_SIZE  = Engine::BLOCK_SIZE,
                DIGEST_SIZE = Engine::DIGEST_SIZE
        };
        
        HMACEngine(const std::string& passphrase)
        {
                init(passphrase.data(), (unsigned) passphrase.length());
        }
        
        HMACEngine(const char* passphrase, unsigned length)
        {
                poco_check_ptr (passphrase);

                init(passphrase, length);
        }
        
        ~HMACEngine()
        {
                std::memset(_ipad, 0, BLOCK_SIZE);
                std::memset(_opad, 0, BLOCK_SIZE);
                delete [] _ipad;
                delete [] _opad;
        }
                
        unsigned digestLength() const
        {
                return DIGEST_SIZE;
        }
        
        void reset()
        {
                _engine.reset();
                _engine.update(_ipad, BLOCK_SIZE);
        }
        
        const DigestEngine::Digest& digest()
        {
                const DigestEngine::Digest& d = _engine.digest();
                char db[DIGEST_SIZE];
                char* pdb = db;
                for (DigestEngine::Digest::const_iterator it = d.begin(); it != d.end(); ++it)
                        *pdb++ = *it;
                _engine.reset();
                _engine.update(_opad, BLOCK_SIZE);
                _engine.update(db, DIGEST_SIZE);
                const DigestEngine::Digest& result = _engine.digest();
                reset();
                return result;
        }

protected:
        void init(const char* passphrase, unsigned length)
        {
                _ipad = new char[BLOCK_SIZE];
                _opad = new char[BLOCK_SIZE];
                std::memset(_ipad, 0, BLOCK_SIZE);
                std::memset(_opad, 0, BLOCK_SIZE);
                if (length > BLOCK_SIZE)
                {
                        _engine.reset();
                        _engine.update(passphrase, length);
                        const DigestEngine::Digest& d = _engine.digest();
                        char* ipad = _ipad;
                        char* opad = _opad;
                        int n = BLOCK_SIZE;
                        for (DigestEngine::Digest::const_iterator it = d.begin(); it != d.end() && n-- > 0; ++it)
                        {
                                *ipad++ = *it;
                                *opad++ = *it;
                        }
                }
                else
                {
                        std::memcpy(_ipad, passphrase, length);
                        std::memcpy(_opad, passphrase, length);
                }
                for (int i = 0; i < BLOCK_SIZE; ++i)
                {
                        _ipad[i] ^= 0x36;
                        _opad[i] ^= 0x5c;
                }
                reset();
        }
        
        void updateImpl(const void* data, unsigned length)
        {
                _engine.update(data, length);
        }

private:
        HMACEngine();
        HMACEngine(const HMACEngine&);
        HMACEngine& operator = (const HMACEngine&);

        Engine _engine;
        char*  _ipad;
        char*  _opad;
};


} // namespace Poco


#endif // Foundation_HMACEngine_INCLUDED