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# arc4.h

    00001 #ifndef CRYPTOPP_ARC4_H
    00002 #define CRYPTOPP_ARC4_H
    00003
    00004 #include "strciphr.h"
    00005
    00006 NAMESPACE_BEGIN(CryptoPP)
    00007
    00008 namespace Weak1 {
    00009
    00010 //! _
    00011 class CRYPTOPP_NO_VTABLE ARC4_Base : public VariableKeyLength<16, 1, 256>, public RandomNumberGenerator, public SymmetricCipher, public SymmetricCipherDocumentation
    00012 {
    00013 public:
    00014         ~ARC4_Base();
    00015
    00016         static const char *StaticAlgorithmName() {return "ARC4";}
    00017
    00018         void GenerateBlock(byte *output, size_t size);
    00019         void DiscardBytes(size_t n);
    00020
    00021     void ProcessData(byte *outString, const byte *inString, size_t length);
    00022
    00023         bool IsRandomAccess() const {return false;}
    00024         bool IsSelfInverting() const {return true;}
    00025         bool IsForwardTransformation() const {return true;}
    00026
    00027         typedef SymmetricCipherFinal<ARC4_Base> Encryption;
    00028         typedef SymmetricCipherFinal<ARC4_Base> Decryption;
    00029
    00030 protected:
    00031         void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params);
    00032         virtual unsigned int GetDefaultDiscardBytes() const {return 0;}
    00033
    00034     FixedSizeSecBlock<byte, 256> m_state;
    00035     byte m_x, m_y;
    00036 };
    00037
    00038 //! <a href="http://www.weidai.com/scan-mirror/cs.html#RC4">Alleged RC4</a>
    00039 DOCUMENTED_TYPEDEF(SymmetricCipherFinal<ARC4_Base>, ARC4)
    00040
    00041 //! _
    00042 class CRYPTOPP_NO_VTABLE MARC4_Base : public ARC4_Base
    00043 {
    00044 public:
    00045         static const char *StaticAlgorithmName() {return "MARC4";}
    00046
    00047         typedef SymmetricCipherFinal<MARC4_Base> Encryption;
    00048         typedef SymmetricCipherFinal<MARC4_Base> Decryption;
    00049
    00050 protected:
    00051         unsigned int GetDefaultDiscardBytes() const {return 256;}
    00052 };
    00053
    00054 //! Modified ARC4: it discards the first 256 bytes of keystream which may be weaker than the rest
    00055 DOCUMENTED_TYPEDEF(SymmetricCipherFinal<MARC4_Base>, MARC4)
    00056
    00057 }
    00058 #if CRYPTOPP_ENABLE_NAMESPACE_WEAK >= 1
    00059 namespace Weak {using namespace Weak1;}         // import Weak1 into CryptoPP::Weak
    00060 #else
    00061 using namespace Weak1;  // import Weak1 into CryptoPP with warning
    00062 #ifdef __GNUC__
    00063 #warning "You may be using a weak algorithm that has been retained for backwards compatibility. Please '#define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1' before including this .h file and prepend the class name with 'Weak::' to remove this warning."
    00064 #else
    00065 #pragma message("You may be using a weak algorithm that has been retained for backwards compatibility. Please '#define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1' before including this .h file and prepend the class name with 'Weak::' to remove this warning.")
    00066 #endif
    00067 #endif
    00068
    00069 NAMESPACE_END
    00070
    00071 #endif