CRYPTOPP_DLL static void ThrowIfTypeMismatch(const char *name, const std::type_info &stored, const std::type_info &retrieving)
		{if (stored != retrieving) throw ValueTypeMismatch(name, stored, retrieving);}

	template <class T>
	void GetRequiredParameter(const char *className, const char *name, T &value) const
	{
		if (!GetValue(name, value))
			throw InvalidArgument(std::string(className) + ": missing required parameter '" + name + "'");
	}

	CRYPTOPP_DLL void GetRequiredIntParameter(const char *className, const char *name, int &value) const
	{
		if (!GetIntValue(name, value))
			throw InvalidArgument(std::string(className) + ": missing required parameter '" + name + "'");
	}

	//! to be implemented by derived classes, users should use one of the above functions instead
	CRYPTOPP_DLL virtual bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const =0;
};

//! namespace containing value name definitions
/*!	value names, types and semantics:

	ThisObject:ClassName (ClassName, copy of this object or a subobject)
	ThisPointer:ClassName (const ClassName *, pointer to this object or a subobject)
*/
DOCUMENTED_NAMESPACE_BEGIN(Name)
// more names defined in argnames.h
DOCUMENTED_NAMESPACE_END

//! empty set of name-value pairs
class CRYPTOPP_DLL NullNameValuePairs : public NameValuePairs
{
public:
	bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const {return false;}
};

//! _
extern CRYPTOPP_DLL const NullNameValuePairs g_nullNameValuePairs;

// ********************************************************

//! interface for cloning objects, this is not implemented by most classes yet
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Clonable
{
public:
	virtual ~Clonable() {}
	//! this is not implemented by most classes yet
	virtual Clonable* Clone() const {throw NotImplemented("Clone() is not implemented yet.");}	// TODO: make this =0
};

//! interface for all crypto algorithms

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Algorithm : public Clonable
{
public:
	/*! When FIPS 140-2 compliance is enabled and checkSelfTestStatus == true,
		this constructor throws SelfTestFailure if the self test hasn't been run or fails. */
	Algorithm(bool checkSelfTestStatus = true);
	//! returns name of this algorithm, not universally implemented yet
	virtual std::string AlgorithmName() const {return "unknown";}
};

//! keying interface for crypto algorithms that take byte strings as keys

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE SimpleKeyingInterface
{
public:
	//! returns smallest valid key length in bytes */
	virtual unsigned int MinKeyLength() const =0;
	//! returns largest valid key length in bytes */
	virtual unsigned int MaxKeyLength() const =0;
	//! returns default (recommended) key length in bytes */
	virtual unsigned int DefaultKeyLength() const =0;

	//! returns the smallest valid key length in bytes that is >= min(n, GetMaxKeyLength())
	virtual unsigned int GetValidKeyLength(unsigned int n) const =0;

	//! returns whether n is a valid key length
	virtual bool IsValidKeyLength(unsigned int n) const
		{return n == GetValidKeyLength(n);}

	//! set or reset the key of this object
	/*! \param params is used to specify Rounds, BlockSize, etc */
	virtual void SetKey(const byte *key, unsigned int length, const NameValuePairs &params = g_nullNameValuePairs) =0;

	//! calls SetKey() with an NameValuePairs object that just specifies "Rounds"
	void SetKeyWithRounds(const byte *key, unsigned int length, int rounds);

	//! calls SetKey() with an NameValuePairs object that just specifies "IV"
	void SetKeyWithIV(const byte *key, unsigned int length, const byte *iv);

	enum IV_Requirement {STRUCTURED_IV = 0, RANDOM_IV, UNPREDICTABLE_RANDOM_IV, INTERNALLY_GENERATED_IV, NOT_RESYNCHRONIZABLE};
	//! returns the minimal requirement for secure IVs
	virtual IV_Requirement IVRequirement() const =0;

	//! returns whether this object can be resynchronized (i.e. supports initialization vectors)
	/*! If this function returns true, and no IV is passed to SetKey() and CanUseStructuredIVs()==true, an IV of all 0's will be assumed. */
	bool IsResynchronizable() const {return IVRequirement() < NOT_RESYNCHRONIZABLE;}
	//! returns whether this object can use random IVs (in addition to ones returned by GetNextIV)
	bool CanUseRandomIVs() const {return IVRequirement() <= UNPREDICTABLE_RANDOM_IV;}
	//! returns whether this object can use random but possibly predictable IVs (in addition to ones returned by GetNextIV)
	bool CanUsePredictableIVs() const {return IVRequirement() <= RANDOM_IV;}
	//! returns whether this object can use structured IVs, for example a counter (in addition to ones returned by GetNextIV)
	bool CanUseStructuredIVs() const {return IVRequirement() <= STRUCTURED_IV;}

	//! returns size of IVs used by this object
	virtual unsigned int IVSize() const {throw NotImplemented("SimpleKeyingInterface: this object doesn't support resynchronization");}
	//! resynchronize with an IV
	virtual void Resynchronize(const byte *IV) {throw NotImplemented("SimpleKeyingInterface: this object doesn't support resynchronization");}
	//! get a secure IV for the next message
	/*! This method should be called after you finish encrypting one message and are ready to start the next one.
		After calling it, you must call SetKey() or Resynchronize() before using this object again. 
		This method is not implemented on decryption objects. */
	virtual void GetNextIV(byte *IV) {throw NotImplemented("SimpleKeyingInterface: this object doesn't support GetNextIV()");}

protected:
	void ThrowIfInvalidKeyLength(const Algorithm &algorithm, unsigned int length);
	void ThrowIfResynchronizable();			// to be called when no IV is passed
	void ThrowIfInvalidIV(const byte *iv);	// check for NULL IV if it can't be used
	const byte * GetIVAndThrowIfInvalid(const NameValuePairs &params);

	inline void AssertValidKeyLength(unsigned int length) const
	{
		assert(IsValidKeyLength(length));
	}
};

//! interface for the data processing part of block ciphers

/*! Classes derived from BlockTransformation are block ciphers
	in ECB mode (for example the DES::Encryption class), which are stateless,
	and they can make assumptions about the memory alignment of their inputs and outputs.
	These classes should not be used directly, but only in combination with
	a mode class (see CipherModeDocumentation in modes.h).
*/
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE BlockTransformation : public Algorithm
{
public:
	//! encrypt or decrypt inBlock, xor with xorBlock, and write to outBlock
	virtual void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const =0;

	//! encrypt or decrypt one block
	/*! \pre size of inBlock and outBlock == BlockSize() */
	void ProcessBlock(const byte *inBlock, byte *outBlock) const
		{ProcessAndXorBlock(inBlock, NULL, outBlock);}

	//! encrypt or decrypt one block in place
	void ProcessBlock(byte *inoutBlock) const
		{ProcessAndXorBlock(inoutBlock, NULL, inoutBlock);}

	//! block size of the cipher in bytes
	virtual unsigned int BlockSize() const =0;

	//! block pointers must be divisible by this
	virtual unsigned int BlockAlignment() const {return 4;}

	//! returns true if this is a permutation (i.e. there is an inverse transformation)
	virtual bool IsPermutation() const {return true;}

	//! returns true if this is an encryption object
	virtual bool IsForwardTransformation() const =0;

	//! return number of blocks that can be processed in parallel, for bit-slicing implementations
	virtual unsigned int OptimalNumberOfParallelBlocks() const {return 1;}

	//! encrypt or decrypt multiple blocks, for bit-slicing implementations
	virtual void ProcessAndXorMultipleBlocks(const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, unsigned int numberOfBlocks) const;
};

//! interface for the data processing part of stream ciphers

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE StreamTransformation : public Algorithm
{
public:
	//! return a reference to this object, 
	/*! This function is useful for passing a temporary StreamTransformation object to a 
		function that takes a non-const reference. */
	StreamTransformation& Ref() {return *this;}

	//! returns block size, if input must be processed in blocks, otherwise 1
	virtual unsigned int MandatoryBlockSize() const {return 1;}

	//! returns the input block size that is most efficient for this cipher
	/*! \note optimal input length is n * OptimalBlockSize() - GetOptimalBlockSizeUsed() for any n > 0 */
	virtual unsigned int OptimalBlockSize() const {return MandatoryBlockSize();}
	//! returns how much of the current block is used up
	virtual unsigned int GetOptimalBlockSizeUsed() const {return 0;}

	//! returns how input should be aligned for optimal performance
	virtual unsigned int OptimalDataAlignment() const {return 1;}

	//! encrypt or decrypt an array of bytes of specified length
	/*! \note either inString == outString, or they don't overlap */
	virtual void ProcessData(byte *outString, const byte *inString, unsigned int length) =0;

	//! for ciphers where the last block of data is special, encrypt or decrypt the last block of data
	/*! For now the only use of this function is for CBC-CTS mode. */
	virtual void ProcessLastBlock(byte *outString, const byte *inString, unsigned int length);
	//! returns the minimum size of the last block, 0 indicating the last block is not special
	virtual unsigned int MinLastBlockSize() const {return 0;}

	//! same as ProcessData(inoutString, inoutString, length)
	inline void ProcessString(byte *inoutString, unsigned int length)
		{ProcessData(inoutString, inoutString, length);}
	//! same as ProcessData(outString, inString, length)
	inline void ProcessString(byte *outString, const byte *inString, unsigned int length)
		{ProcessData(outString, inString, length);}
	//! implemented as {ProcessData(&input, &input, 1); return input;}
	inline byte ProcessByte(byte input)
		{ProcessData(&input, &input, 1); return input;}

	//! returns whether this cipher supports random access
	virtual bool IsRandomAccess() const =0;
	//! for random access ciphers, seek to an absolute position
	virtual void Seek(lword n)
	{
		assert(!IsRandomAccess());
		throw NotImplemented("StreamTransformation: this object doesn't support random access");
	}

	//! returns whether this transformation is self-inverting (e.g. xor with a keystream)
	virtual bool IsSelfInverting() const =0;
	//! returns whether this is an encryption object
	virtual bool IsForwardTransformation() const =0;
};

//! interface for hash functions and data processing part of MACs

/*! HashTransformation objects are stateful.  They are created in an initial state,
	change state as Update() is called, and return to the initial
	state when Final() is called.  This interface allows a large message to
	be hashed in pieces by calling Update() on each piece followed by
	calling Final().
*/
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE HashTransformation : public Algorithm
{
public:
	//! process more input
	virtual void Update(const byte *input, unsigned int length) =0;

	//! request space to write input into
	virtual byte * CreateUpdateSpace(unsigned int &size) {size=0; return NULL;}

	//! compute hash for current message, then restart for a new message
	/*!	\pre size of digest == DigestSize(). */
	virtual void Final(byte *digest)
		{TruncatedFinal(digest, DigestSize());}

	//! discard the current state, and restart with a new message
	virtual void Restart()
		{TruncatedFinal(NULL, 0);}

	//! size of the hash returned by Final()
	virtual unsigned int DigestSize() const =0;

	//! block size of underlying compression function, or 0 if not block based
	virtual unsigned int BlockSize() const {return 0;}

	//! input to Update() should have length a multiple of this for optimal speed
	virtual unsigned int OptimalBlockSize() const {return 1;}

	//! returns how input should be aligned for optimal performance
	virtual unsigned int OptimalDataAlignment() const {return 1;}

	//! use this if your input is in one piece and you don't want to call Update() and Final() separately
	virtual void CalculateDigest(byte *digest, const byte *input, unsigned int length)
		{Update(input, length); Final(digest);}

	//! verify that digest is a valid digest for the current message, then reinitialize the object
	/*! Default implementation is to call Final() and do a bitwise comparison
		between its output and digest. */
	virtual bool Verify(const byte *digest)
		{return TruncatedVerify(digest, DigestSize());}

	//! use this if your input is in one piece and you don't want to call Update() and Verify() separately
	virtual bool VerifyDigest(const byte *digest, const byte *input, unsigned int length)
		{Update(input, length); return Verify(digest);}

	//! truncated version of Final()
	virtual void TruncatedFinal(byte *digest, unsigned int digestSize) =0;

	//! truncated version of CalculateDigest()
	virtual void CalculateTruncatedDigest(byte *digest, unsigned int digestSize, const byte *input, unsigned int length)
		{Update(input, length); TruncatedFinal(digest, digestSize);}