140 lines
5.0 KiB
C++
140 lines
5.0 KiB
C++
// gcm.h - originally written and placed in the public domain by Wei Dai
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/// \file gcm.h
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/// \brief GCM block cipher mode of operation
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/// \since Crypto++ 5.6.0
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#ifndef CRYPTOPP_GCM_H
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#define CRYPTOPP_GCM_H
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#include "authenc.h"
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#include "modes.h"
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// Clang 3.3 integrated assembler crash on Linux. Clang 3.4 due to compiler
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// error with .intel_syntax, http://llvm.org/bugs/show_bug.cgi?id=24232
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#if CRYPTOPP_BOOL_X32 || defined(CRYPTOPP_DISABLE_MIXED_ASM)
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# define CRYPTOPP_DISABLE_GCM_ASM 1
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#endif
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NAMESPACE_BEGIN(CryptoPP)
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/// \enum GCM_TablesOption
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/// \brief GCM table size options
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enum GCM_TablesOption {
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/// \brief Use a table with 2K entries
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GCM_2K_Tables,
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/// \brief Use a table with 64K entries
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GCM_64K_Tables};
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/// \brief GCM block cipher base implementation
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/// \details Base implementation of the AuthenticatedSymmetricCipher interface
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/// \since Crypto++ 5.6.0
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class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE GCM_Base : public AuthenticatedSymmetricCipherBase
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{
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public:
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// AuthenticatedSymmetricCipher
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std::string AlgorithmName() const
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{return GetBlockCipher().AlgorithmName() + std::string("/GCM");}
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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();}
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size_t MaxKeyLength() const
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{return GetBlockCipher().MaxKeyLength();}
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size_t DefaultKeyLength() const
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{return GetBlockCipher().DefaultKeyLength();}
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size_t GetValidKeyLength(size_t n) const
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{return GetBlockCipher().GetValidKeyLength(n);}
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bool IsValidKeyLength(size_t n) const
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{return GetBlockCipher().IsValidKeyLength(n);}
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unsigned int OptimalDataAlignment() const;
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IV_Requirement IVRequirement() const
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{return UNIQUE_IV;}
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unsigned int IVSize() const
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{return 12;}
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unsigned int MinIVLength() const
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{return 1;}
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unsigned int MaxIVLength() const
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{return UINT_MAX;} // (W64LIT(1)<<61)-1 in the standard
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unsigned int DigestSize() const
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{return 16;}
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lword MaxHeaderLength() const
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{return (W64LIT(1)<<61)-1;}
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lword MaxMessageLength() const
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{return ((W64LIT(1)<<39)-256)/8;}
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protected:
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// AuthenticatedSymmetricCipherBase
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bool AuthenticationIsOnPlaintext() const
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{return false;}
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unsigned int AuthenticationBlockSize() const
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{return HASH_BLOCKSIZE;}
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void SetKeyWithoutResync(const byte *userKey, size_t keylength, const NameValuePairs ¶ms);
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void Resync(const byte *iv, size_t len);
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size_t AuthenticateBlocks(const byte *data, size_t len);
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void AuthenticateLastHeaderBlock();
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void AuthenticateLastConfidentialBlock();
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void AuthenticateLastFooterBlock(byte *mac, size_t macSize);
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SymmetricCipher & AccessSymmetricCipher() {return m_ctr;}
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virtual BlockCipher & AccessBlockCipher() =0;
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virtual GCM_TablesOption GetTablesOption() const =0;
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const BlockCipher & GetBlockCipher() const {return const_cast<GCM_Base *>(this)->AccessBlockCipher();}
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byte *HashBuffer() {return m_buffer+REQUIRED_BLOCKSIZE;}
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byte *HashKey() {return m_buffer+2*REQUIRED_BLOCKSIZE;}
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byte *MulTable() {return m_buffer+3*REQUIRED_BLOCKSIZE;}
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inline void ReverseHashBufferIfNeeded();
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class CRYPTOPP_DLL GCTR : public CTR_Mode_ExternalCipher::Encryption
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{
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protected:
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void IncrementCounterBy256();
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};
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GCTR m_ctr;
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static word16 s_reductionTable[256];
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static volatile bool s_reductionTableInitialized;
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enum {REQUIRED_BLOCKSIZE = 16, HASH_BLOCKSIZE = 16};
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};
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/// \brief GCM block cipher final implementation
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/// \tparam T_BlockCipher block cipher
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/// \tparam T_TablesOption table size, either \p GCM_2K_Tables or \p GCM_64K_Tables
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/// \tparam T_IsEncryption direction in which to operate the cipher
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/// \since Crypto++ 5.6.0
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template <class T_BlockCipher, GCM_TablesOption T_TablesOption, bool T_IsEncryption>
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class GCM_Final : public GCM_Base
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{
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public:
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static std::string StaticAlgorithmName()
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{return T_BlockCipher::StaticAlgorithmName() + std::string("/GCM");}
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bool IsForwardTransformation() const
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{return T_IsEncryption;}
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private:
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GCM_TablesOption GetTablesOption() const {return T_TablesOption;}
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BlockCipher & AccessBlockCipher() {return m_cipher;}
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typename T_BlockCipher::Encryption m_cipher;
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};
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/// \brief GCM block cipher mode of operation
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/// \tparam T_BlockCipher block cipher
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/// \tparam T_TablesOption table size, either \p GCM_2K_Tables or \p GCM_64K_Tables
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/// \details \p GCM provides the \p Encryption and \p Decryption typedef. See GCM_Base
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/// and GCM_Final for the AuthenticatedSymmetricCipher implementation.
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/// \sa <a href="http://www.cryptopp.com/wiki/GCM_Mode">GCM Mode</a> and
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/// <A HREF="http://www.cryptopp.com/wiki/Modes_of_Operation">Modes of Operation</A>
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/// on the Crypto++ wiki.
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/// \since Crypto++ 5.6.0
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template <class T_BlockCipher, GCM_TablesOption T_TablesOption=GCM_2K_Tables>
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struct GCM : public AuthenticatedSymmetricCipherDocumentation
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{
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typedef GCM_Final<T_BlockCipher, T_TablesOption, true> Encryption;
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typedef GCM_Final<T_BlockCipher, T_TablesOption, false> Decryption;
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};
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NAMESPACE_END
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#endif
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