The LUC inverse function. More...

#include <luc.h>

Inheritance diagram for InvertibleLUCFunction:

Public Member Functions
void	Initialize (RandomNumberGenerator &rng, unsigned int modulusBits, const Integer &eStart=17)
	Create a LUC private key.

void	Initialize (const Integer &n, const Integer &e, const Integer &p, const Integer &q, const Integer &u)
	Initialize a LUC private key with {n,e,p,q,dp,dq,u}.

void	BERDecode (BufferedTransformation &bt)

void	DEREncode (BufferedTransformation &bt) const

Integer	CalculateInverse (RandomNumberGenerator &rng, const Integer &x) const
	Calculates the inverse of an element.

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

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

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

void	GenerateRandom (RandomNumberGenerator &rng, const NameValuePairs &alg)

const Integer &	GetPrime1 () const

const Integer &	GetPrime2 () const

const Integer &	GetMultiplicativeInverseOfPrime2ModPrime1 () const

void	SetPrime1 (const Integer &p)

void	SetPrime2 (const Integer &q)

void	SetMultiplicativeInverseOfPrime2ModPrime1 (const Integer &u)

Public Member Functions inherited from LUCFunction
void	Initialize (const Integer &n, const Integer &e)
	Initialize a LUC public key with {n,e}.

void	BERDecode (BufferedTransformation &bt)

void	DEREncode (BufferedTransformation &bt) const

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

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

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

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

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

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

const Integer &	GetModulus () const

const Integer &	GetPublicExponent () const

void	SetModulus (const Integer &n)

void	SetPublicExponent (const Integer &e)

Public Member Functions inherited from TrapdoorFunction
Integer	ApplyRandomizedFunction (RandomNumberGenerator &rng, const Integer &x) const
	Applies the trapdoor function.

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

Public Member Functions inherited from TrapdoorFunctionBounds
virtual Integer	MaxPreimage () const
	Returns the maximum size of a message before the trapdoor function is applied bound to a public key.

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

Public Member Functions inherited from CryptoMaterial
virtual void	ThrowIfInvalid (RandomNumberGenerator &rng, unsigned int level) const
	Check this object for errors.

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

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

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

virtual void	Precompute (unsigned int precomputationStorage)
	Perform precomputation.

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

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

void	DoQuickSanityCheck () const
	Perform a quick sanity check.

Public Member Functions inherited from NameValuePairs
template<class T >
bool	GetThisObject (T &object) const
	Get a copy of this object or subobject.

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

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

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

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

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

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

CRYPTOPP_DLL bool	GetWord64Value (const char *name, word64 &value) const
	Get a named value with type word64.

CRYPTOPP_DLL word64	GetWord64ValueWithDefault (const char *name, word64 defaultValue) const
	Get a named value with type word64, with default.

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

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

Public Member Functions inherited from TrapdoorFunctionInverse
Integer	CalculateRandomizedInverse (RandomNumberGenerator &rng, const Integer &x) const
	Applies the inverse of the trapdoor function.

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

Public Member Functions inherited from GeneratableCryptoMaterial
void	GenerateRandomWithKeySize (RandomNumberGenerator &rng, unsigned int keySize)
	Generate a random key or crypto parameters.

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

Detailed Description

The LUC inverse 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.

Since: Crypto++ 2.1

Definition at line 78 of file luc.h.

Constructor & Destructor Documentation

◆ ~InvertibleLUCFunction()

virtual InvertibleLUCFunction::~InvertibleLUCFunction ( )

inlinevirtual

Definition at line 83 of file luc.h.

Member Function Documentation

◆ Initialize() [1/2]

void InvertibleLUCFunction::Initialize	(	RandomNumberGenerator &	rng,
		unsigned int	modulusBits,
		const Integer &	eStart = 17 )

Create a LUC private key.

Parameters

rng	a RandomNumberGenerator derived class
modulusBits	the size of the modulus, in bits
eStart	the desired starting public exponent

Initialize() creates a new keypair using a starting public exponent of 17.

This function overload of Initialize() creates a new keypair because it takes a RandomNumberGenerator() as a parameter. If you have an existing keypair, then use one of the other Initialize() overloads.

Definition at line 137 of file luc.cpp.

◆ Initialize() [2/2]

void InvertibleLUCFunction::Initialize	(	const Integer &	n,
		const Integer &	e,
		const Integer &	p,
		const Integer &	q,
		const Integer &	u )

inline

Initialize a LUC private key with {n,e,p,q,dp,dq,u}.

Parameters

n	modulus
e	public exponent
p	first prime factor
q	second prime factor
u	q^-1 mod p

This Initialize() function overload initializes a private key from existing parameters.

Definition at line 102 of file luc.h.

◆ BERDecode()

void InvertibleLUCFunction::BERDecode ( BufferedTransformation & bt )

Definition at line 142 of file luc.cpp.

◆ DEREncode()

void InvertibleLUCFunction::DEREncode ( BufferedTransformation & bt ) const

Definition at line 158 of file luc.cpp.

◆ CalculateInverse()

Integer InvertibleLUCFunction::CalculateInverse	(	RandomNumberGenerator &	rng,
		const Integer &	x ) const

virtual

Calculates the inverse of an element.

Parameters

rng	a RandomNumberGenerator derived class
x	the element

Returns: the inverse of the element in the group

Implements TrapdoorFunctionInverse.

Definition at line 172 of file luc.cpp.

◆ Validate()

bool InvertibleLUCFunction::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.

See also: ThrowIfInvalid()

Implements CryptoMaterial.

Definition at line 180 of file luc.cpp.

◆ GetVoidValue()

bool InvertibleLUCFunction::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.

Definition at line 213 of file luc.cpp.

◆ AssignFrom()

void InvertibleLUCFunction::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.

Definition at line 222 of file luc.cpp.

◆ GenerateRandom()

void InvertibleLUCFunction::GenerateRandom	(	RandomNumberGenerator &	rng,
		const NameValuePairs &	alg )

virtual

parameters: (ModulusSize, PublicExponent (default 17))

Reimplemented from GeneratableCryptoMaterial.

Definition at line 114 of file luc.cpp.

◆ GetPrime1()

const Integer & InvertibleLUCFunction::GetPrime1 ( ) const

inline

Definition at line 117 of file luc.h.

◆ GetPrime2()

const Integer & InvertibleLUCFunction::GetPrime2 ( ) const

inline

Definition at line 118 of file luc.h.

◆ GetMultiplicativeInverseOfPrime2ModPrime1()

const Integer & InvertibleLUCFunction::GetMultiplicativeInverseOfPrime2ModPrime1 ( ) const

inline

Definition at line 119 of file luc.h.

◆ SetPrime1()

void InvertibleLUCFunction::SetPrime1 ( const Integer & p )

inline

Definition at line 121 of file luc.h.

◆ SetPrime2()

void InvertibleLUCFunction::SetPrime2 ( const Integer & q )

inline

Definition at line 122 of file luc.h.

◆ SetMultiplicativeInverseOfPrime2ModPrime1()

void InvertibleLUCFunction::SetMultiplicativeInverseOfPrime2ModPrime1 ( const Integer & u )

inline

Definition at line 123 of file luc.h.

The documentation for this class was generated from the following files:

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~InvertibleLUCFunction()

Member Function Documentation

◆ Initialize() [1/2]

◆ Initialize() [2/2]

◆ BERDecode()

◆ DEREncode()

◆ CalculateInverse()

◆ Validate()

◆ GetVoidValue()

◆ AssignFrom()

◆ GenerateRandom()

◆ GetPrime1()

◆ GetPrime2()

◆ GetMultiplicativeInverseOfPrime2ModPrime1()

◆ SetPrime1()

◆ SetPrime2()

◆ SetMultiplicativeInverseOfPrime2ModPrime1()