//----------------------------------------------------------------------------
//
// TSDuck - The MPEG Transport Stream Toolkit
// Copyright (c) 2005-2020, Thierry Lelegard
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
//    this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
//
//----------------------------------------------------------------------------
//!
//!  @file
//!  DES block cipher
//!
//----------------------------------------------------------------------------

#pragma once
#include "tsBlockCipher.h"

namespace ts {
    //!
    //! DES block cipher.
    //! @ingroup crypto
    //!
    class TSDUCKDLL DES: public BlockCipher
    {
        TS_NOCOPY(DES);
    public:
        DES();                                   //!< Constructor.
        static constexpr size_t BLOCK_SIZE = 8;  //!< DES block size in bytes.
        static constexpr size_t KEY_SIZE = 8;    //!< DES key size in bytes.
        static constexpr size_t ROUNDS = 16;     //!< DES number of rounds.

        // Implementation of BlockCipher interface:
        virtual UString name() const override;
        virtual size_t blockSize() const override;
        virtual size_t minKeySize() const override;
        virtual size_t maxKeySize() const override;
        virtual bool isValidKeySize (size_t size) const override;
        virtual size_t minRounds() const override;
        virtual size_t maxRounds() const override;
        virtual size_t defaultRounds() const override;

    protected:
        // Implementation of BlockCipher interface:
        virtual bool setKeyImpl(const void* key, size_t key_length, size_t rounds) override;
        virtual bool encryptImpl(const void* plain, size_t plain_length, void* cipher, size_t cipher_maxsize, size_t* cipher_length) override;
        virtual bool decryptImpl(const void* cipher, size_t cipher_length, void* plain, size_t plain_maxsize, size_t* plain_length) override;

    private:
        uint32_t _ek[32];  // Encryption keys
        uint32_t _dk[32];  // Decryption keys

        // Computation static methods, shared with TDES
        friend class TDES;
        static const uint16_t EN0 = 0;
        static const uint16_t DE1 = 1;
        static void cookey(const uint32_t* raw1, uint32_t* keyout);
        static void deskey(const uint8_t* key, uint16_t edf, uint32_t* keyout);
        static void desfunc(uint32_t* block, const uint32_t* keys);
    };
}
