225 lines
10 KiB
C++
225 lines
10 KiB
C++
// xts.h - written and placed in the public domain by Jeffrey Walton
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/// \file xts.h
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/// \brief Classes for XTS block cipher mode of operation
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/// \details XTS mode is a wide block mode defined by IEEE P1619-2008. NIST
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/// SP-800-38E approves the mode for storage devices citing IEEE 1619-2007.
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/// IEEE 1619-2007 provides both a reference implementation and test vectors.
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/// The IEEE reference implementation fails to arrive at the expected result
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/// for some test vectors.
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/// \sa <A HREF="http://www.cryptopp.com/wiki/Modes_of_Operation">Modes of
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/// Operation</A> on the Crypto++ wiki, <A
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/// HREF="https://web.cs.ucdavis.edu/~rogaway/papers/modes.pdf"> Evaluation of Some
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/// Blockcipher Modes of Operation</A>, <A
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/// HREF="https://csrc.nist.gov/publications/detail/sp/800-38e/final">Recommendation
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/// for Block Cipher Modes of Operation: The XTS-AES Mode for Confidentiality on
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/// Storage Devices</A>, <A
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/// HREF="http://libeccio.di.unisa.it/Crypto14/Lab/p1619.pdf">IEEE P1619-2007</A>
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/// and <A HREF="https://crypto.stackexchange.com/q/74925/10496">IEEE P1619/XTS,
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/// inconsistent reference implementation and test vectors</A>.
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/// \since Crypto++ 8.3
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#ifndef CRYPTOPP_XTS_MODE_H
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#define CRYPTOPP_XTS_MODE_H
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#include "cryptlib.h"
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#include "secblock.h"
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#include "modes.h"
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#include "misc.h"
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/// \brief Enable XTS for wide block ciphers
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/// \details XTS is only defined for AES. The library can support wide
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/// block ciphers like Kaylna and Threefish since we know the polynomials.
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/// To enable wide block ciphers define <tt>CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS</tt>
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/// to non-zero. Note this is a library compile time define.
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/// \details There is risk involved with using XTS with wider block ciphers.
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/// According to Phillip Rogaway, "The narrow width of the underlying PRP and
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/// the poor treatment of fractional final blocks are problems."
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/// \sa <A HREF="https://web.cs.ucdavis.edu/~rogaway/papers/modes.pdf">Evaluation
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/// of Some Blockcipher Modes of Operation</A>
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/// \since Crypto++ 8.3
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#ifndef CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS
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# define CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS 0
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#endif // CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief XTS block cipher mode of operation default implementation
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/// \since Crypto++ 8.3
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class CRYPTOPP_NO_VTABLE XTS_ModeBase : public BlockOrientedCipherModeBase
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{
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public:
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/// \brief The algorithm name
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/// \return the algorithm name
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/// \details StaticAlgorithmName returns the algorithm's name as a static
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/// member function.
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CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName()
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{return "XTS";}
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virtual ~XTS_ModeBase() {}
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std::string AlgorithmName() const
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{return GetBlockCipher().AlgorithmName() + "/XTS";}
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std::string AlgorithmProvider() const
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{return GetBlockCipher().AlgorithmProvider();}
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size_t MinKeyLength() const
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{return GetBlockCipher().MinKeyLength()*2;}
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size_t MaxKeyLength() const
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{return GetBlockCipher().MaxKeyLength()*2;}
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size_t DefaultKeyLength() const
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{return GetBlockCipher().DefaultKeyLength()*2;}
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size_t GetValidKeyLength(size_t n) const
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{return 2*GetBlockCipher().GetValidKeyLength((n+1)/2);}
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bool IsValidKeyLength(size_t keylength) const
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{return keylength == GetValidKeyLength(keylength);}
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/// \brief Validates the key length
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/// \param length the size of the keying material, in bytes
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/// \throw InvalidKeyLength if the key length is invalid
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void ThrowIfInvalidKeyLength(size_t length);
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/// Provides the block size of the cipher
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/// \return the block size of the cipher, in bytes
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unsigned int BlockSize() const
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{return GetBlockCipher().BlockSize();}
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/// \brief Provides the input block size most efficient for this cipher
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/// \return The input block size that is most efficient for the cipher
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/// \details The base class implementation returns MandatoryBlockSize().
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/// \note Optimal input length is
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/// <tt>n * OptimalBlockSize() - GetOptimalBlockSizeUsed()</tt> for
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/// any <tt>n \> 0</tt>.
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unsigned int GetOptimalBlockSize() const
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{return GetBlockCipher().BlockSize()*ParallelBlocks;}
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unsigned int MinLastBlockSize() const
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{return GetBlockCipher().BlockSize()+1;}
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unsigned int OptimalDataAlignment() const
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{return GetBlockCipher().OptimalDataAlignment();}
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/// \brief Validates the block size
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/// \param length the block size of the cipher, in bytes
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/// \throw InvalidArgument if the block size is invalid
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/// \details If <tt>CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS</tt> is 0,
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/// then CIPHER must be a 16-byte block cipher. If
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/// <tt>CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS</tt> is non-zero then
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/// CIPHER can be 16, 32, 64, or 128-byte block cipher.
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void ThrowIfInvalidBlockSize(size_t length);
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void SetKey(const byte *key, size_t length, const NameValuePairs ¶ms = g_nullNameValuePairs);
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IV_Requirement IVRequirement() const {return UNIQUE_IV;}
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void Resynchronize(const byte *iv, int ivLength=-1);
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void ProcessData(byte *outString, const byte *inString, size_t length);
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size_t ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength);
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/// \brief Resynchronize the cipher
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/// \param sector a 64-bit sector number
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/// \param order the endian order the word should be written
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/// \details The Resynchronize() overload was provided for API
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/// compatibility with the IEEE P1619 paper.
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void Resynchronize(word64 sector, ByteOrder order=BIG_ENDIAN_ORDER);
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protected:
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virtual void ResizeBuffers();
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inline size_t ProcessLastPlainBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength);
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inline size_t ProcessLastCipherBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength);
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virtual BlockCipher& AccessBlockCipher() = 0;
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virtual BlockCipher& AccessTweakCipher() = 0;
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const BlockCipher& GetBlockCipher() const
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{return const_cast<XTS_ModeBase*>(this)->AccessBlockCipher();}
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const BlockCipher& GetTweakCipher() const
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{return const_cast<XTS_ModeBase*>(this)->AccessTweakCipher();}
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// Buffers are sized based on ParallelBlocks
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AlignedSecByteBlock m_xregister;
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AlignedSecByteBlock m_xworkspace;
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// Intel lacks the SSE registers to run 8 or 12 parallel blocks.
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// Do not change this value after compiling. It has no effect.
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#if CRYPTOPP_BOOL_X64 || CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X86
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enum {ParallelBlocks = 4};
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#else
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enum {ParallelBlocks = 12};
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#endif
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};
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/// \brief XTS block cipher mode of operation implementation
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/// \tparam CIPHER BlockCipher derived class or type
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/// \details XTS_Final() provides access to CIPHER in base class XTS_ModeBase()
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/// through an interface. AccessBlockCipher() and AccessTweakCipher() allow
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/// the XTS_ModeBase() base class to access the user's block cipher without
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/// recompiling the library.
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/// \details If <tt>CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS</tt> is 0, then CIPHER must
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/// be a 16-byte block cipher. If <tt>CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS</tt> is
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/// non-zero then CIPHER can be 16, 32, 64, or 128-byte block cipher.
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/// There is risk involved with using XTS with wider block ciphers.
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/// According to Phillip Rogaway, "The narrow width of the underlying PRP and
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/// the poor treatment of fractional final blocks are problems." To enable
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/// wide block cipher support define <tt>CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS</tt> to
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/// non-zero.
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/// \sa <A HREF="http://www.cryptopp.com/wiki/Modes_of_Operation">Modes of
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/// Operation</A> on the Crypto++ wiki, <A
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/// HREF="https://web.cs.ucdavis.edu/~rogaway/papers/modes.pdf"> Evaluation of Some
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/// Blockcipher Modes of Operation</A>, <A
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/// HREF="https://csrc.nist.gov/publications/detail/sp/800-38e/final">Recommendation
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/// for Block Cipher Modes of Operation: The XTS-AES Mode for Confidentiality on
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/// Storage Devices</A>, <A
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/// HREF="http://libeccio.di.unisa.it/Crypto14/Lab/p1619.pdf">IEEE P1619-2007</A>
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/// and <A HREF="https://crypto.stackexchange.com/q/74925/10496">IEEE P1619/XTS,
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/// inconsistent reference implementation and test vectors</A>.
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/// \since Crypto++ 8.3
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template <class CIPHER>
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class CRYPTOPP_NO_VTABLE XTS_Final : public XTS_ModeBase
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{
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protected:
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BlockCipher& AccessBlockCipher()
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{return *m_cipher;}
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BlockCipher& AccessTweakCipher()
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{return m_tweaker;}
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protected:
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typename CIPHER::Encryption m_tweaker;
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};
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/// \brief XTS block cipher mode of operation
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/// \tparam CIPHER BlockCipher derived class or type
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/// \details XTS mode is a wide block mode defined by IEEE P1619-2008. NIST
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/// SP-800-38E approves the mode for storage devices citing IEEE 1619-2007.
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/// IEEE 1619-2007 provides both a reference implementation and test vectors.
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/// The IEEE reference implementation fails to arrive at the expected result
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/// for some test vectors.
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/// \details XTS is only defined for AES. The library can support wide
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/// block ciphers like Kaylna and Threefish since we know the polynomials.
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/// There is risk involved with using XTS with wider block ciphers.
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/// According to Phillip Rogaway, "The narrow width of the underlying PRP and
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/// the poor treatment of fractional final blocks are problems." To enable
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/// wide block cipher support define <tt>CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS</tt> to
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/// non-zero.
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/// \sa <A HREF="http://www.cryptopp.com/wiki/Modes_of_Operation">Modes of
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/// Operation</A> on the Crypto++ wiki, <A
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/// HREF="https://web.cs.ucdavis.edu/~rogaway/papers/modes.pdf"> Evaluation of Some
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/// Blockcipher Modes of Operation</A>, <A
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/// HREF="https://csrc.nist.gov/publications/detail/sp/800-38e/final">Recommendation
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/// for Block Cipher Modes of Operation: The XTS-AES Mode for Confidentiality on
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/// Storage Devices</A>, <A
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/// HREF="http://libeccio.di.unisa.it/Crypto14/Lab/p1619.pdf">IEEE P1619-2007</A>
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/// and <A HREF="https://crypto.stackexchange.com/q/74925/10496">IEEE P1619/XTS,
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/// inconsistent reference implementation and test vectors</A>.
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/// \since Crypto++ 8.3
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template <class CIPHER>
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struct XTS : public CipherModeDocumentation
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{
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typedef CipherModeFinalTemplate_CipherHolder<typename CIPHER::Encryption, XTS_Final<CIPHER> > Encryption;
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typedef CipherModeFinalTemplate_CipherHolder<typename CIPHER::Decryption, XTS_Final<CIPHER> > Decryption;
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};
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// C++03 lacks the mechanics to typedef a template
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#define XTS_Mode XTS
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NAMESPACE_END
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#endif // CRYPTOPP_XTS_MODE_H
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