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1 files changed, 59 insertions, 0 deletions

diff --git a/arc4.h b/arc4.h
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+#ifndef CRYPTOPP_ARC4_H
+#define CRYPTOPP_ARC4_H
+
+#include "strciphr.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+//! <a href="http://www.weidai.com/scan-mirror/cs.html#RC4">Alleged RC4</a>
+/*! You can #ARC4 typedef rather than this class directly. */
+class ARC4_Base : public VariableKeyLength<16, 1, 256>, public RandomNumberGenerator, public SymmetricCipher
+{
+public:
+	~ARC4_Base();
+
+	static const char *StaticAlgorithmName() {return "ARC4";}
+
+    byte GenerateByte();
+	void DiscardBytes(unsigned int n);
+
+    void ProcessData(byte *outString, const byte *inString, unsigned int length);
+	
+	bool IsRandomAccess() const {return false;}
+	bool IsSelfInverting() const {return true;}
+	bool IsForwardTransformation() const {return true;}
+
+	typedef SymmetricCipherFinalTemplate<ARC4_Base> Encryption;
+	typedef SymmetricCipherFinalTemplate<ARC4_Base> Decryption;
+
+protected:
+	void UncheckedSetKey(const NameValuePairs &params, const byte *key, unsigned int length);
+	virtual unsigned int GetDefaultDiscardBytes() const {return 0;}
+
+    FixedSizeSecBlock<byte, 256> m_state;
+    byte m_x, m_y;
+};
+
+//! .
+typedef SymmetricCipherFinalTemplate<ARC4_Base> ARC4;
+
+//! Modified ARC4: it discards the first 256 bytes of keystream which may be weaker than the rest
+/*! You can #MARC4 typedef rather than this class directly. */
+class MARC4_Base : public ARC4_Base
+{
+public:
+	static const char *StaticAlgorithmName() {return "MARC4";}
+
+	typedef SymmetricCipherFinalTemplate<MARC4_Base> Encryption;
+	typedef SymmetricCipherFinalTemplate<MARC4_Base> Decryption;
+
+protected:
+	unsigned int GetDefaultDiscardBytes() const {return 256;}
+};
+
+//! .
+typedef SymmetricCipherFinalTemplate<MARC4_Base> MARC4;
+
+NAMESPACE_END
+
+#endif