eax.h

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


#ifndef CRYPTOPP_EAX_H
#define CRYPTOPP_EAX_H

#include "authenc.h"
#include "modes.h"
#include "cmac.h"

NAMESPACE_BEGIN(CryptoPP)

class CRYPTOPP_NO_VTABLE EAX_Base : public AuthenticatedSymmetricCipherBase
{
public:
        // AuthenticatedSymmetricCipher
        std::string AlgorithmName() const
                {return GetMAC().GetCipher().AlgorithmName() + std::string("/EAX");}
        size_t MinKeyLength() const
                {return GetMAC().MinKeyLength();}
        size_t MaxKeyLength() const
                {return GetMAC().MaxKeyLength();}
        size_t DefaultKeyLength() const
                {return GetMAC().DefaultKeyLength();}
        size_t GetValidKeyLength(size_t n) const
                {return GetMAC().GetValidKeyLength(n);}
        bool IsValidKeyLength(size_t n) const
                {return GetMAC().IsValidKeyLength(n);}
        unsigned int OptimalDataAlignment() const
                {return GetMAC().OptimalDataAlignment();}
        IV_Requirement IVRequirement() const
                {return UNIQUE_IV;}
        unsigned int IVSize() const
                {return GetMAC().TagSize();}
        unsigned int MinIVLength() const
                {return 0;}
        unsigned int MaxIVLength() const
                {return UINT_MAX;}
        unsigned int DigestSize() const
                {return GetMAC().TagSize();}
        lword MaxHeaderLength() const
                {return LWORD_MAX;}
        lword MaxMessageLength() const
                {return LWORD_MAX;}

protected:
        // AuthenticatedSymmetricCipherBase
        bool AuthenticationIsOnPlaintext() const
                {return false;}
        unsigned int AuthenticationBlockSize() const
                {return 1;}
        void SetKeyWithoutResync(const byte *userKey, size_t keylength, const NameValuePairs &params);
        void Resync(const byte *iv, size_t len);
        size_t AuthenticateBlocks(const byte *data, size_t len);
        void AuthenticateLastHeaderBlock();
        void AuthenticateLastFooterBlock(byte *mac, size_t macSize);
        SymmetricCipher & AccessSymmetricCipher() {return m_ctr;}
        const CMAC_Base & GetMAC() const {return const_cast<EAX_Base *>(this)->AccessMAC();}
        virtual CMAC_Base & AccessMAC() =0;

        CTR_Mode_ExternalCipher::Encryption m_ctr;
};

template <class T_BlockCipher, bool T_IsEncryption>
class EAX_Final : public EAX_Base
{
public:
        static std::string StaticAlgorithmName()
                {return T_BlockCipher::StaticAlgorithmName() + std::string("/EAX");}
        bool IsForwardTransformation() const
                {return T_IsEncryption;}

private:
        CMAC_Base & AccessMAC() {return m_cmac;}
        CMAC<T_BlockCipher> m_cmac;
};

#ifdef EAX      // EAX is defined to 11 on GCC 3.4.3, OpenSolaris 8.11
#undef EAX
#endif

template <class T_BlockCipher>
struct EAX : public AuthenticatedSymmetricCipherDocumentation
{
        typedef EAX_Final<T_BlockCipher, true> Encryption;
        typedef EAX_Final<T_BlockCipher, false> Decryption;
};

NAMESPACE_END

#endif