ESIGN trapdoor function using the public key. More...

#include <esign.h>

Inheritance diagram for ESIGNFunction:

Collaboration diagram for ESIGNFunction:

Public Member Functions
void	Initialize (const Integer &n, const Integer &e)
	Initialize a ESIGN public key with {n,e}. More...

void	BERDecode (BufferedTransformation &bt)
	Decode this object from a BufferedTransformation. More...

void	DEREncode (BufferedTransformation &bt) const
	Encode this object into a BufferedTransformation. 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...

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...

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 ASN1CryptoMaterial< PublicKey >
void	Save (BufferedTransformation &bt) const
	DER encode ASN.1 object. More...

void	Load (BufferedTransformation &bt)
	BER decode ASN.1 object. More...

Public Member Functions inherited from ASN1Object
virtual	~ASN1Object ()

virtual void	BEREncode (BufferedTransformation &bt) const
	Encode this object into a BufferedTransformation. 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 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 Member Functions
unsigned int	GetK () const

Protected Attributes
Integer	m_n

Integer	m_e

Private Types
typedef ESIGNFunction	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

ESIGN trapdoor function using the public key.

Since: Crypto++ 5.0

Definition at line 21 of file esign.h.

Member Typedef Documentation

typedef ESIGNFunction ESIGNFunction::ThisClass

private

Definition at line 23 of file esign.h.

Member Function Documentation

Integer ESIGNFunction::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 53 of file esign.cpp.

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void ESIGNFunction::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 InvertibleESIGNFunction.

Definition at line 76 of file esign.cpp.

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void ESIGNFunction::BERDecode ( BufferedTransformation & bt )

virtual

Decode this object from a BufferedTransformation.

Parameters

bt	BufferedTransformation object

Uses Basic Encoding Rules (BER)

Implements ASN1Object.

Reimplemented in InvertibleESIGNFunction.

Definition at line 37 of file esign.cpp.

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void ESIGNFunction::DEREncode ( BufferedTransformation & bt ) const

virtual

Encode this object into a BufferedTransformation.

Parameters

bt	BufferedTransformation object

Uses Distinguished Encoding Rules (DER)

Implements ASN1Object.

Reimplemented in InvertibleESIGNFunction.

Definition at line 45 of file esign.cpp.

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unsigned int ESIGNFunction::GetK ( ) const

inlineprotected

Definition at line 56 of file esign.h.

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const Integer& ESIGNFunction::GetModulus ( ) const

inline

Definition at line 48 of file esign.h.

const Integer& ESIGNFunction::GetPublicExponent ( ) const

inline

Definition at line 49 of file esign.h.

bool ESIGNFunction::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 InvertibleESIGNFunction.

Definition at line 68 of file esign.cpp.

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Integer ESIGNFunction::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 45 of file esign.h.

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

inline

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

Parameters

n	the modulus
e	the public exponent

Definition at line 30 of file esign.h.

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Integer ESIGNFunction::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 44 of file esign.h.

void ESIGNFunction::SetModulus ( const Integer & n )

inline

Definition at line 51 of file esign.h.

void ESIGNFunction::SetPublicExponent ( const Integer & e )

inline

Definition at line 52 of file esign.h.

bool ESIGNFunction::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.