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Cipher.h

//
// Cipher.h
//
// $Id: //poco/1.3/Crypto/include/Poco/Crypto/Cipher.h#3 $
//
// Library: Crypto
// Package: Cipher
// Module:  Cipher
//
// Definition of the Cipher class.
//
// 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.
//


#ifndef Crypto_Cipher_INCLUDED
#define Crypto_Cipher_INCLUDED


#include "Poco/Crypto/Crypto.h"
#include "Poco/RefCountedObject.h"
#include "Poco/AutoPtr.h"
#include <istream>
#include <ostream>
#include <vector>


namespace Poco {
namespace Crypto {


class CryptoTransform;


00058 class Crypto_API Cipher: public Poco::RefCountedObject
      /// Represents the abstract base class from which all implementations of
      /// symmetric/assymetric encryption algorithms must inherit.  Use the CipherFactory
      /// class to obtain an instance of this class:
      ///
      ///     CipherFactory& factory = CipherFactory::defaultFactory();
      ///     // Creates a 256-bit AES cipher
      ///     Cipher* pCipher = factory.createCipher(CipherKey("aes-256"));
      ///     Cipher* pRSACipher = factory.createCipher(RSAKey(RSAKey::KL_1024, RSAKey::EXP_SMALL));
      ///
      /// Check the different Key constructors on how to initialize/create
      /// a key. The above example auto-generates random keys.
      ///
      /// Note that you won't be able to decrypt data encrypted with a random key
      /// once the Cipher is destroyed unless you persist the generated key and IV.
      /// An example usage for random keys is to encrypt data saved in a temporary
      /// file.
      ///
      /// Once your key is set up, you can use the Cipher object to encrypt or
      /// decrypt strings or, in conjunction with a CryptoInputStream or a
      /// CryptoOutputStream, to encrypt streams of data.
      ///
      /// Since encrypted strings will contain arbitary binary data that will cause
      /// problems in applications that are not binary-safe (eg., when sending
      /// encrypted data in e-mails), the encryptString() and decryptString() can
      /// encode (or decode, respectively) encrypted data using a "transport encoding".
      /// Supported encodings are Base64 and BinHex.
      ///
      /// The following example encrypts and decrypts a string utilizing Base64
      /// encoding:
      ///
      ///     std::string plainText = "This is my secret information";
      ///     std::string encrypted = pCipher->encryptString(plainText, Cipher::ENC_BASE64);
      ///     std::string decrypted = pCipher->decryptString(encrypted, Cipher::ENC_BASE64);
      ///
      /// In order to encrypt a stream of data (eg. to encrypt files), you can use
      /// a CryptoStream:
      ///
      ///     // Create an output stream that will encrypt all data going through it
      ///     // and write pass it to the underlying file stream.
      ///     Poco::FileOutputStream sink("encrypted.dat");
      ///     CryptoOutputStream encryptor(sink, pCipher->createEncryptor());
      ///     
      ///     Poco::FileInputStream source("source.txt");
      ///     Poco::StreamCopier::copyStream(source, encryptor);
      ///     
      ///     // Always close output streams to flush all internal buffers
      ///     encryptor.close();
      ///     sink.close();
{
public:
      typedef Poco::AutoPtr<Cipher> Ptr;
      typedef std::vector<unsigned char> ByteVec;

00112       enum Encoding
            /// Transport encoding to use for encryptString() and decryptString().
      {
            ENC_NONE,         /// Plain binary output
00116             ENC_BASE64,       /// Base64-encoded output
00117             ENC_BINHEX        /// BinHex-encoded output
      };

      virtual ~Cipher();
            /// Destroys the Cipher.

      virtual const std::string& name() const = 0;
            /// Returns the name of the Cipher.

      virtual CryptoTransform* createEncryptor() = 0;
            /// Creates an encrytor object to be used with a CryptoStream.

      virtual CryptoTransform* createDecryptor() = 0;
            /// Creates a decryptor object to be used with a CryptoStream.

      virtual std::string encryptString(const std::string& str, Encoding encoding = ENC_NONE);
            /// Directly encrypt a string and encode it using the given encoding.

      virtual std::string decryptString(const std::string& str, Encoding encoding = ENC_NONE);
            /// Directly decrypt a string that is encoded with the given encoding.

      virtual void encrypt(std::istream& source, std::ostream& sink, Encoding encoding = ENC_NONE);
            /// Directly encrypts an input stream and encodes it using the given encoding.

      virtual void decrypt(std::istream& source, std::ostream& sink, Encoding encoding = ENC_NONE);
            /// Directly decrypt an input stream that is encoded with the given encoding.

protected:
      Cipher();
            /// Creates a new Cipher object.

private:
      Cipher(const Cipher&);
      Cipher& operator = (const Cipher&);
};


} } // namespace Poco::Crypto


#endif // Crypto_Cipher_INCLUDED

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