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seal.h

#ifndef CRYPTOPP_SEAL_H
#define CRYPTOPP_SEAL_H

#include "cryptlib.h"
#include "misc.h"

NAMESPACE_BEGIN(CryptoPP)

class SEAL : public RandomNumberGenerator,
                         public RandomAccessStreamCipher
{
public:
        // If you plan to encrypt more than one message with a key,
        // you must call NextCount() after each message, save the count,
        // and initialize SEAL with it for the next message.
        SEAL(const byte *key, word32 counter = 0, unsigned int L = 32*1024);

        word32 NextCount() const {return counter+1;}

        byte GenerateByte();
        byte ProcessByte(byte input)
                {return (input ^ SEAL::GenerateByte());}

        void ProcessString(byte *outString, const byte *inString, unsigned int length);
        void ProcessString(byte *inoutString, unsigned int length)
                {SEAL::ProcessString(inoutString, inoutString, length);}

        void Seek(unsigned long position);

        enum {KEYLENGTH=20};

protected:
        void Generate(word32 in, byte *out) const;
        void IncrementCounter();

private:
        const unsigned int L;
        SecBlock<word32> R, S, T;

        const word32 startCount;
        word32 counter;
        unsigned int position;
        SecByteBlock buffer;
};

NAMESPACE_END

#endif

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