1 // seal.h - written and placed in the public domain by Wei Dai 2 3 //! \file seal.h 4 //! \brief Classes for SEAL stream cipher 5 6 #ifndef CRYPTOPP_SEAL_H 7 #define CRYPTOPP_SEAL_H 8 9 #include "strciphr.h" 10 #include "secblock.h" 11 12 NAMESPACE_BEGIN(CryptoPP) 13 14 //! \class SEAL_Info 15 //! \brief SEAL stream cipher information 16 //! \tparam B Endianness of the stream cipher 17 template <class B = BigEndian> 18 struct SEAL_Info : public FixedKeyLength<20, SimpleKeyingInterface::INTERNALLY_GENERATED_IV, 4> 19 { StaticAlgorithmNameSEAL_Info20 CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return B::ToEnum() == LITTLE_ENDIAN_ORDER ? "SEAL-3.0-LE" : "SEAL-3.0-BE";} 21 }; 22 23 //! \class SEAL_Policy 24 //! \brief SEAL stream cipher operation 25 //! \tparam B Endianness of the stream cipher 26 template <class B = BigEndian> 27 class CRYPTOPP_NO_VTABLE SEAL_Policy : public AdditiveCipherConcretePolicy<word32, 256>, public SEAL_Info<B> 28 { 29 protected: 30 void CipherSetKey(const NameValuePairs ¶ms, const byte *key, size_t length); 31 void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount); 32 void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length); CipherIsRandomAccess()33 bool CipherIsRandomAccess() const {return true;} 34 void SeekToIteration(lword iterationCount); 35 36 private: 37 FixedSizeSecBlock<word32, 512> m_T; 38 FixedSizeSecBlock<word32, 256> m_S; 39 SecBlock<word32> m_R; 40 41 word32 m_startCount, m_iterationsPerCount; 42 word32 m_outsideCounter, m_insideCounter; 43 }; 44 45 //! \class SEAL 46 //! \brief SEAL stream cipher 47 //! \tparam B Endianness of the stream cipher 48 //! \sa <a href="http://www.weidai.com/scan-mirror/cs.html#SEAL-3.0-BE">SEAL</a> 49 template <class B = BigEndian> 50 struct SEAL : public SEAL_Info<B>, public SymmetricCipherDocumentation 51 { 52 typedef SymmetricCipherFinal<ConcretePolicyHolder<SEAL_Policy<B>, AdditiveCipherTemplate<> >, SEAL_Info<B> > Encryption; 53 typedef Encryption Decryption; 54 }; 55 56 NAMESPACE_END 57 58 #endif 59