The LUC function. More...

#include <luc.h>

Inheritance diagram for LUCFunction:

Collaboration diagram for LUCFunction:

Public Member Functions
virtual	~LUCFunction ()

void	Initialize (const Integer &n, const Integer &e)
	Initialize a LUC public key with {n,e}. More...

void	BERDecode (BufferedTransformation &bt)

void	DEREncode (BufferedTransformation &bt) const

Integer	ApplyFunction (const Integer &x) const
	Applies the trapdoor. More...

Integer	PreimageBound () const
	Returns the maximum size of a message before the trapdoor function is applied. More...

Integer	ImageBound () const
	Returns the maximum size of a message after the trapdoor function is applied. More...

bool	Validate (RandomNumberGenerator &rng, unsigned int level) const
	Check this object for errors. More...

bool	GetVoidValue (const char name, const std::type_info &valueType, void pValue) const
	Get a named value. More...

void	AssignFrom (const NameValuePairs &source)
	Assign values to this object. More...

const Integer &	GetModulus () const

const Integer &	GetPublicExponent () const

void	SetModulus (const Integer &n)

void	SetPublicExponent (const Integer &e)

Public Member Functions inherited from TrapdoorFunction
virtual	~TrapdoorFunction ()

Integer	ApplyRandomizedFunction (RandomNumberGenerator &rng, const Integer &x) const
	Applies the trapdoor function. More...

bool	IsRandomized () const
	Determines if the encryption algorithm is randomized. More...

Public Member Functions inherited from RandomizedTrapdoorFunction
virtual	~RandomizedTrapdoorFunction ()

Public Member Functions inherited from TrapdoorFunctionBounds
virtual	~TrapdoorFunctionBounds ()

virtual Integer	MaxPreimage () const
	Returns the maximum size of a message before the trapdoor function is applied bound to a public key. More...

virtual Integer	MaxImage () const
	Returns the maximum size of a message after the trapdoor function is applied bound to a public key. More...

Public Member Functions inherited from CryptoMaterial
virtual	~CryptoMaterial ()

virtual void	ThrowIfInvalid (RandomNumberGenerator &rng, unsigned int level) const
	Check this object for errors. More...

virtual void	Save (BufferedTransformation &bt) const
	Saves a key to a BufferedTransformation. More...

virtual void	Load (BufferedTransformation &bt)
	Loads a key from a BufferedTransformation. More...

virtual bool	SupportsPrecomputation () const
	Determines whether the object supports precomputation. More...

virtual void	Precompute (unsigned int precomputationStorage)
	Perform precomputation. More...

virtual void	LoadPrecomputation (BufferedTransformation &storedPrecomputation)
	Retrieve previously saved precomputation. More...

virtual void	SavePrecomputation (BufferedTransformation &storedPrecomputation) const
	Save precomputation for later use. More...

void	DoQuickSanityCheck () const
	Perform a quick sanity check. More...

Public Member Functions inherited from NameValuePairs
virtual	~NameValuePairs ()

template<class T >
bool	GetThisObject (T &object) const
	Get a copy of this object or subobject. More...

template<class T >
bool	GetThisPointer (T *&ptr) const
	Get a pointer to this object. More...

template<class T >
bool	GetValue (const char *name, T &value) const
	Get a named value. More...

template<class T >
T	GetValueWithDefault (const char *name, T defaultValue) const
	Get a named value. More...

CRYPTOPP_DLL std::string	GetValueNames () const
	Get a list of value names that can be retrieved. More...

CRYPTOPP_DLL bool	GetIntValue (const char *name, int &value) const
	Get a named value with type int. More...

CRYPTOPP_DLL int	GetIntValueWithDefault (const char *name, int defaultValue) const
	Get a named value with type int, with default. More...

template<class T >
void	GetRequiredParameter (const char className, const char name, T &value) const
	Retrieves a required name/value pair. More...

CRYPTOPP_DLL void	GetRequiredIntParameter (const char className, const char name, int &value) const
	Retrieves a required name/value pair. More...

Protected Attributes
Integer	m_n

Integer	m_e

Private Types
typedef LUCFunction	ThisClass

Additional Inherited Members
Static Public Member Functions inherited from NameValuePairs
static CRYPTOPP_DLL void CRYPTOPP_API	ThrowIfTypeMismatch (const char *name, const std::type_info &stored, const std::type_info &retrieving)
	Ensures an expected name and type is present. More...

Detailed Description

The LUC function.

This class is here for historical and pedagogical interest. It has no practical advantages over other trapdoor functions and probably shouldn't be used in production software. The discrete log based LUC schemes defined later in this .h file may be of more practical interest.

Definition at line 36 of file luc.h.

Member Typedef Documentation

typedef LUCFunction LUCFunction::ThisClass

private

Definition at line 38 of file luc.h.

Constructor & Destructor Documentation

virtual LUCFunction::~LUCFunction ( )

inlinevirtual

Definition at line 41 of file luc.h.

Member Function Documentation

Integer LUCFunction::ApplyFunction ( const Integer & x ) const

virtual

Applies the trapdoor.

Parameters

x	the message on which the encryption function is applied

Returns: the message x encrypted under the public key

ApplyFunction is a generalization of encryption under a public key cryptosystem. Derived classes must implement it.

Implements TrapdoorFunction.

Definition at line 66 of file luc.cpp.

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void LUCFunction::AssignFrom ( const NameValuePairs & source )

virtual

Assign values to this object.

This function can be used to create a public key from a private key.

Implements CryptoMaterial.

Reimplemented in InvertibleLUCFunction.

Definition at line 89 of file luc.cpp.

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void LUCFunction::BERDecode ( BufferedTransformation & bt )

Definition at line 50 of file luc.cpp.

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void LUCFunction::DEREncode ( BufferedTransformation & bt ) const

Definition at line 58 of file luc.cpp.

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const Integer& LUCFunction::GetModulus ( ) const

inline

Definition at line 61 of file luc.h.

const Integer& LUCFunction::GetPublicExponent ( ) const

inline

Definition at line 62 of file luc.h.

bool LUCFunction::GetVoidValue	(	const char *	name,
		const std::type_info &	valueType,
		void *	pValue
	)		const

virtual

Get a named value.

Parameters

name	the name of the object or value to retrieve
valueType	reference to a variable that receives the value
pValue	void pointer to a variable that receives the value

Returns: true if the value was retrieved, false otherwise

GetVoidValue() retrieves the value of name if it exists.

Note: GetVoidValue() is an internal function and should be implemented by derived classes. Users should use one of the other functions instead.

See also: GetValue(), GetValueWithDefault(), GetIntValue(), GetIntValueWithDefault(), GetRequiredParameter() and GetRequiredIntParameter()

Implements NameValuePairs.

Reimplemented in InvertibleLUCFunction.

Definition at line 81 of file luc.cpp.

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Integer LUCFunction::ImageBound ( ) const

inlinevirtual

Returns the maximum size of a message after the trapdoor function is applied.

Returns: the maximum size of a message after the trapdoor function is applied

Derived classes must implement ImageBound().

Implements TrapdoorFunctionBounds.

Definition at line 54 of file luc.h.

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void LUCFunction::Initialize	(	const Integer &	n,
		const Integer &	e
	)

inline

Initialize a LUC public key with {n,e}.

Parameters

n	the modulus
e	the public exponent

Definition at line 46 of file luc.h.

Integer LUCFunction::PreimageBound ( ) const

inlinevirtual

Returns the maximum size of a message before the trapdoor function is applied.

Returns: the maximum size of a message before the trapdoor function is applied

Derived classes must implement PreimageBound().

Implements TrapdoorFunctionBounds.

Definition at line 53 of file luc.h.

void LUCFunction::SetModulus ( const Integer & n )

inline

Definition at line 64 of file luc.h.

void LUCFunction::SetPublicExponent ( const Integer & e )

inline

Definition at line 65 of file luc.h.

bool LUCFunction::Validate	(	RandomNumberGenerator &	rng,
		unsigned int	level
	)		const

virtual

Check this object for errors.

Parameters

rng	a RandomNumberGenerator for objects which use randomized testing
level	the level of thoroughness

Returns: true if the tests succeed, false otherwise

There are four levels of thoroughness:

0 - using this object won't cause a crash or exception
1 - this object will probably function, and encrypt, sign, other operations correctly
2 - ensure this object will function correctly, and perform reasonable security checks
3 - perform reasonable security checks, and do checks that may take a long time

Level 0 does not require a RandomNumberGenerator. A NullRNG() can be used for level 0. Level 1 may not check for weak keys and such. Levels 2 and 3 are recommended.