Logo Search packages:      
Sourcecode: poco version File versions

CipherImpl.cpp

//
// CipherImpl.cpp
//
// $Id: //poco/1.4/Crypto/src/CipherImpl.cpp#2 $
//
// Library: Crypto
// Package: Cipher
// Module:  CipherImpl
//
// Copyright (c) 2008, 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.
//


#include "Poco/Crypto/CipherImpl.h"
#include "Poco/Crypto/CryptoTransform.h"
#include "Poco/Exception.h"
#include <openssl/err.h>


namespace Poco {
namespace Crypto {


namespace
{
      void throwError()
      {
            unsigned long err;
            std::string msg;
            
            while ((err = ERR_get_error()))
            {
                  if (!msg.empty())
                        msg.append("; ");
                  msg.append(ERR_error_string(err, 0));
            }

            throw Poco::IOException(msg);
      }


      class CryptoTransformImpl: public CryptoTransform
      {
      public:
            typedef Cipher::ByteVec ByteVec;

            enum Direction
            {
                  DIR_ENCRYPT,
                  DIR_DECRYPT
            };

            CryptoTransformImpl(
                  const EVP_CIPHER* pCipher,
                  const ByteVec&    key,
                  const ByteVec&    iv,
                  Direction         dir);

            ~CryptoTransformImpl();
            
            std::size_t blockSize() const;

            std::streamsize transform(
                  const unsigned char* input,
                  std::streamsize      inputLength,
                  unsigned char*       output,
                  std::streamsize      outputLength);
            
            std::streamsize finalize(
                  unsigned char*  output,
                  std::streamsize length);

      private:
            const EVP_CIPHER* _pCipher;
            EVP_CIPHER_CTX    _ctx;
            ByteVec           _key;
            ByteVec           _iv;
      };


      CryptoTransformImpl::CryptoTransformImpl(
            const EVP_CIPHER* pCipher,
            const ByteVec&    key,
            const ByteVec&    iv,
            Direction         dir):
            _pCipher(pCipher),
            _key(key),
            _iv(iv)
      {
            EVP_CipherInit(
                  &_ctx,
                  _pCipher,
                  &_key[0],
                  &_iv[0],
                  (dir == DIR_ENCRYPT) ? 1 : 0);
      }


      CryptoTransformImpl::~CryptoTransformImpl()
      {
            EVP_CIPHER_CTX_cleanup(&_ctx);
      }


      std::size_t CryptoTransformImpl::blockSize() const
      {
            return EVP_CIPHER_CTX_block_size(&_ctx);
      }


      std::streamsize CryptoTransformImpl::transform(
            const unsigned char* input,
            std::streamsize      inputLength,
            unsigned char*       output,
            std::streamsize      outputLength)
      {
            poco_assert (outputLength >= (inputLength + blockSize() - 1));

            int outLen = static_cast<int>(outputLength);
            int rc = EVP_CipherUpdate(
                  &_ctx,
                  output,
                  &outLen,
                  input,
                  static_cast<int>(inputLength));

            if (rc == 0)
                  throwError();

            return static_cast<std::streamsize>(outLen);
      }


      std::streamsize CryptoTransformImpl::finalize(
            unsigned char*    output,
            std::streamsize length)
      {
            poco_assert (length >= blockSize());
            
            int len = static_cast<int>(length);

            // Use the '_ex' version that does not perform implicit cleanup since we
            // will call EVP_CIPHER_CTX_cleanup() from the dtor as there is no
            // guarantee that finalize() will be called if an error occurred.
            int rc = EVP_CipherFinal_ex(&_ctx, output, &len);

            if (rc == 0)
                  throwError();
                  
            return static_cast<std::streamsize>(len);
      }
}


CipherImpl::CipherImpl(const CipherKey& key):
      _key(key)
{
}


00184 CipherImpl::~CipherImpl()
{
}


00189 CryptoTransform* CipherImpl::createEncryptor()
{
      CipherKeyImpl::Ptr p = _key.impl();
      return new CryptoTransformImpl(p->cipher(), p->getKey(), p->getIV(), CryptoTransformImpl::DIR_ENCRYPT);
}


00196 CryptoTransform* CipherImpl::createDecryptor()
{
      CipherKeyImpl::Ptr p = _key.impl();
      return new CryptoTransformImpl(p->cipher(), p->getKey(), p->getIV(), CryptoTransformImpl::DIR_DECRYPT);
}


} } // namespace Poco::Crypto

Generated by  Doxygen 1.6.0   Back to index