topical media & game development
lib-of-vs-libs-Poco-include-Poco-HMACEngine.h / h
//
// HMACEngine.h
//
//
//
// 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
(C) Æliens
04/09/2009
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