XTS.h

/*
 * Copyright (C) 2016 Southern Storm Software, Pty Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * 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 AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF 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_XTS_h
#define CRYPTO_XTS_h

#include "BlockCipher.h"

class XTSSingleKeyCommon;

class XTSCommon
{
public:
    virtual ~XTSCommon();

    virtual size_t keySize() const;
    size_t tweakSize() const;

    size_t sectorSize() const { return sectSize; }
    bool setSectorSize(size_t size);

    virtual bool setKey(const uint8_t *key, size_t len);
    bool setTweak(const uint8_t *tweak, size_t len);

    void encryptSector(uint8_t *output, const uint8_t *input);
    void decryptSector(uint8_t *output, const uint8_t *input);

    void clear();

protected:
    XTSCommon();
    void setBlockCiphers(BlockCipher *cipher1, BlockCipher *cipher2)
    {
        blockCipher1 = cipher1;
        blockCipher2 = cipher2;
    }

private:
    BlockCipher *blockCipher1;
    BlockCipher *blockCipher2;
    uint32_t twk[4];
    size_t sectSize;

    friend class XTSSingleKeyCommon;
};

class XTSSingleKeyCommon : public XTSCommon
{
public:
    virtual ~XTSSingleKeyCommon();

    size_t keySize() const;
    bool setKey(const uint8_t *key, size_t len);

protected:
    XTSSingleKeyCommon() : XTSCommon() {}
};

template <typename T1, typename T2 = T1>
class XTS : public XTSCommon
{
public:
    XTS() { setBlockCiphers(&cipher1, &cipher2); }
    ~XTS() {}

private:
    T1 cipher1;
    T2 cipher2;
};

template <typename T>
class XTSSingleKey : public XTSSingleKeyCommon
{
public:
    XTSSingleKey() { setBlockCiphers(&cipher, &cipher); }
    ~XTSSingleKey() {}

private:
    T cipher;
};

#endif