Initial revision

1 files changed, 138 insertions, 0 deletions

diff --git a/lubyrack.h b/lubyrack.h
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+// lubyrack.h - written and placed in the public domain by Wei Dai
+
+#ifndef CRYPTOPP_LUBYRACK_H
+#define CRYPTOPP_LUBYRACK_H
+
+/** \file */
+
+#include "simple.h"
+#include "secblock.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+template <class T> struct DigestSizeDoubleWorkaround {enum {RESULT = 2*T::DIGESTSIZE};};	// VC60 workaround
+
+//! .
+template <class T>
+struct LR_Info : public VariableKeyLength<16, 0, 2*(UINT_MAX/2), 2>, public FixedBlockSize<DigestSizeDoubleWorkaround<T>::RESULT>
+{
+	static std::string StaticAlgorithmName() {return std::string("LR/")+T::StaticAlgorithmName();}
+};
+
+//! Luby-Rackoff
+template <class T>
+class LR : public LR_Info<T>, public BlockCipherDocumentation
+{
+	class Base : public BlockCipherBaseTemplate<LR_Info<T> >
+	{
+	public:
+		// VC60 workaround: have to define these functions within class definition
+		void UncheckedSetKey(CipherDir direction, const byte *userKey, unsigned int length)
+		{
+			AssertValidKeyLength(length);
+
+			L = length/2;
+			buffer.New(2*S);
+			digest.New(S);
+			key.Assign(userKey, 2*L);
+		}
+
+	protected:
+		enum {S=T::DIGESTSIZE};
+		unsigned int L;	// key length / 2
+		SecByteBlock key;
+
+		mutable T hm;
+		mutable SecByteBlock buffer, digest;
+	};
+
+	class Enc : public Base
+	{
+	public:
+
+#define KL key
+#define KR key+L
+#define BL buffer
+#define BR buffer+S
+#define IL inBlock
+#define IR inBlock+S
+#define OL outBlock
+#define OR outBlock+S
+
+		void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
+		{
+			hm.Update(KL, L);
+			hm.Update(IL, S);
+			hm.Final(BR);
+			xorbuf(BR, IR, S);
+
+			hm.Update(KR, L);
+			hm.Update(BR, S);
+			hm.Final(BL);
+			xorbuf(BL, IL, S);
+
+			hm.Update(KL, L);
+			hm.Update(BL, S);
+			hm.Final(digest);
+			xorbuf(BR, digest, S);
+
+			hm.Update(KR, L);
+			hm.Update(OR, S);
+			hm.Final(digest);
+			xorbuf(BL, digest, S);
+
+			if (xorBlock)
+				xorbuf(outBlock, xorBlock, buffer, 2*S);
+			else
+				memcpy(outBlock, buffer, 2*S);
+		}
+	};
+
+	class Dec : public Base
+	{
+	public:
+		void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
+		{
+			hm.Update(KR, L);
+			hm.Update(IR, S);
+			hm.Final(BL);
+			xorbuf(BL, IL, S);
+
+			hm.Update(KL, L);
+			hm.Update(BL, S);
+			hm.Final(BR);
+			xorbuf(BR, IR, S);
+
+			hm.Update(KR, L);
+			hm.Update(BR, S);
+			hm.Final(digest);
+			xorbuf(BL, digest, S);
+
+			hm.Update(KL, L);
+			hm.Update(OL, S);
+			hm.Final(digest);
+			xorbuf(BR, digest, S);
+
+			if (xorBlock)
+				xorbuf(outBlock, xorBlock, buffer, 2*S);
+			else
+				memcpy(outBlock, buffer, 2*S);
+		}
+#undef KL
+#undef KR
+#undef BL
+#undef BR
+#undef IL
+#undef IR
+#undef OL
+#undef OR
+	};
+
+public:
+	typedef BlockCipherTemplate<ENCRYPTION, Enc> Encryption;
+	typedef BlockCipherTemplate<DECRYPTION, Dec> Decryption;
+};
+
+NAMESPACE_END
+
+#endif