Rabin-Williams trapdoor function using the private key. More...

#include <rw.h>

Inheritance diagram for InvertibleRWFunction:

Public Member Functions
	InvertibleRWFunction ()
	Construct an InvertibleRWFunction.

void	Initialize (const Integer &n, const Integer &p, const Integer &q, const Integer &u)
	Initialize a Rabin-Williams private key.

void	Initialize (RandomNumberGenerator &rng, unsigned int modulusBits)
	Create a Rabin-Williams private key.

void	BERDecode (BufferedTransformation &bt)

void	DEREncode (BufferedTransformation &bt) const

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

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

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)

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

virtual void	Precompute (unsigned int unused=0)
	Perform precomputation.

virtual void	Precompute (unsigned int unused=0) const

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

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

Public Member Functions inherited from RWFunction
void	Initialize (const Integer &n)
	Initialize a Rabin-Williams public key.

void	BERDecode (BufferedTransformation &bt)

void	DEREncode (BufferedTransformation &bt) const

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

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

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

void	SetModulus (const Integer &n)

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.

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

Rabin-Williams trapdoor function using the private key.

Since: Crypto++ 3.0, Tweaked roots using e and f since Crypto++ 5.6.4

Definition at line 59 of file rw.h.

Constructor & Destructor Documentation

◆ InvertibleRWFunction()

InvertibleRWFunction::InvertibleRWFunction ( )

inline

Construct an InvertibleRWFunction.

Definition at line 65 of file rw.h.

Member Function Documentation

◆ Initialize() [1/2]

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

Initialize a Rabin-Williams private key.

Parameters

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

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

◆ Initialize() [2/2]

void InvertibleRWFunction::Initialize	(	RandomNumberGenerator &	rng,
		unsigned int	modulusBits )

inline

Create a Rabin-Williams private key.

Parameters

rng	a RandomNumberGenerator derived class
modulusBits	the size of the modulus, in bits

This function overload of Initialize() creates a new private key 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 81 of file rw.h.

◆ Save()

void InvertibleRWFunction::Save ( BufferedTransformation & bt ) const

inlinevirtual

Saves a key to a BufferedTransformation.

Parameters

bt	the destination BufferedTransformation

Exceptions

NotImplemented

Save() writes the material to a BufferedTransformation.

If the material is a key, then the key is written with ASN.1 DER encoding. The key includes an object identifier with an algorithm id, like a subjectPublicKeyInfo.

A "raw" key without the "key info" can be saved using a key's DEREncode() method.

If a derived class does not override Save(), then the base class throws NotImplemented().

Reimplemented from CryptoMaterial.

Definition at line 87 of file rw.h.

◆ Load()

void InvertibleRWFunction::Load ( BufferedTransformation & bt )

inlinevirtual

Loads a key from a BufferedTransformation.

Parameters

bt	the source BufferedTransformation

Exceptions

KeyingErr

Load() attempts to read material from a BufferedTransformation. If the material is a key that was generated outside the library, then the following usually applies:

the key should be ASN.1 BER encoded
the key should be a "key info"

"key info" means the key should have an object identifier with an algorithm id, like a subjectPublicKeyInfo.

To read a "raw" key without the "key info", then call the key's BERDecode() method.

Note: Load() generally does not check that the key is valid. Call Validate(), if needed.

Reimplemented from CryptoMaterial.

Definition at line 89 of file rw.h.

◆ CalculateInverse()

Integer InvertibleRWFunction::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.

◆ Validate()

bool InvertibleRWFunction::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.

◆ GetVoidValue()

bool InvertibleRWFunction::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.

◆ AssignFrom()

void InvertibleRWFunction::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.

◆ GenerateRandom()

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

virtual

parameters: (ModulusSize)

Reimplemented from GeneratableCryptoMaterial.

◆ GetPrime1()

const Integer & InvertibleRWFunction::GetPrime1 ( ) const

inline

Definition at line 101 of file rw.h.

◆ GetPrime2()

const Integer & InvertibleRWFunction::GetPrime2 ( ) const

inline

Definition at line 102 of file rw.h.

◆ GetMultiplicativeInverseOfPrime2ModPrime1()

const Integer & InvertibleRWFunction::GetMultiplicativeInverseOfPrime2ModPrime1 ( ) const

inline

Definition at line 103 of file rw.h.

◆ SetPrime1()

void InvertibleRWFunction::SetPrime1 ( const Integer & p )

inline

Definition at line 105 of file rw.h.

◆ SetPrime2()

void InvertibleRWFunction::SetPrime2 ( const Integer & q )

inline

Definition at line 106 of file rw.h.

◆ SetMultiplicativeInverseOfPrime2ModPrime1()

void InvertibleRWFunction::SetMultiplicativeInverseOfPrime2ModPrime1 ( const Integer & u )

inline

Definition at line 107 of file rw.h.

◆ SupportsPrecomputation()

virtual bool InvertibleRWFunction::SupportsPrecomputation ( ) const

inlinevirtual

Determines whether the object supports precomputation.

Returns: true if the object supports precomputation, false otherwise

See also: Precompute()

Reimplemented from CryptoMaterial.

Definition at line 109 of file rw.h.

◆ Precompute() [1/2]

virtual void InvertibleRWFunction::Precompute ( unsigned int precomputationStorage = 0 )

inlinevirtual

Perform precomputation.

Parameters

precomputationStorage the suggested number of objects for the precompute table

Exceptions

NotImplemented

The exact semantics of Precompute() varies, but it typically means calculate a table of n objects that can be used later to speed up computation.

If a derived class does not override Precompute(), then the base class throws NotImplemented.

See also: SupportsPrecomputation(), LoadPrecomputation(), SavePrecomputation()

Reimplemented from CryptoMaterial.

Definition at line 110 of file rw.h.

◆ Precompute() [2/2]

virtual void InvertibleRWFunction::Precompute ( unsigned int unused = 0 ) const

inlinevirtual

Definition at line 111 of file rw.h.

◆ LoadPrecomputation()

virtual void InvertibleRWFunction::LoadPrecomputation ( BufferedTransformation & storedPrecomputation )

virtual

Retrieve previously saved precomputation.

Parameters

storedPrecomputation BufferedTransformation with the saved precomputation

Exceptions

NotImplemented

See also: SupportsPrecomputation(), Precompute()

Reimplemented from CryptoMaterial.

◆ SavePrecomputation()

virtual void InvertibleRWFunction::SavePrecomputation ( BufferedTransformation & storedPrecomputation ) const

virtual

Save precomputation for later use.

Parameters

storedPrecomputation BufferedTransformation to write the precomputation

Exceptions

NotImplemented

See also: SupportsPrecomputation(), Precompute()

Reimplemented from CryptoMaterial.

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

rw.h

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ InvertibleRWFunction()

Member Function Documentation

◆ Initialize() [1/2]

◆ Initialize() [2/2]

◆ Save()

◆ Load()

◆ CalculateInverse()

◆ Validate()

◆ GetVoidValue()

◆ AssignFrom()

◆ GenerateRandom()

◆ GetPrime1()

◆ GetPrime2()

◆ GetMultiplicativeInverseOfPrime2ModPrime1()

◆ SetPrime1()

◆ SetPrime2()

◆ SetMultiplicativeInverseOfPrime2ModPrime1()

◆ SupportsPrecomputation()

◆ Precompute() [1/2]

◆ Precompute() [2/2]

◆ LoadPrecomputation()

◆ SavePrecomputation()