salsa.h

// salsa.h - written and placed in the public domain by Wei Dai

#ifndef CRYPTOPP_SALSA_H
#define CRYPTOPP_SALSA_H

#include "strciphr.h"

NAMESPACE_BEGIN(CryptoPP)

//! _
struct Salsa20_Info : public VariableKeyLength<32, 16, 32, 16, SimpleKeyingInterface::STRUCTURED_IV, 8>
{
        static const char *StaticAlgorithmName() {return "Salsa20";}
};

class CRYPTOPP_NO_VTABLE Salsa20_Policy : public AdditiveCipherConcretePolicy<word32, 16>, public Salsa20_Info
{
protected:
        void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);
        void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);
        void CipherGetNextIV(byte *IV);
        void CipherResynchronize(byte *keystreamBuffer, const byte *IV);
        bool IsRandomAccess() const {return true;}
        void SeekToIteration(lword iterationCount);

private:
        int m_rounds;
        FixedSizeSecBlock<word32, 16> m_state;
};

//! Salsa20, variable rounds: 8, 12 or 20 (default 20)
struct Salsa20 : public Salsa20_Info, public SymmetricCipherDocumentation
{
        typedef SymmetricCipherFinal<ConcretePolicyHolder<Salsa20_Policy, AdditiveCipherTemplate<> >, Salsa20_Info> Encryption;
        typedef Encryption Decryption;
};

NAMESPACE_END

#endif

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