DSA group parameters. More...

#include <gfpcrypt.h>

Inheritance diagram for DL_GroupParameters_DSA:

Public Types
enum	{ MIN_PRIME_LENGTH = 1024 , MAX_PRIME_LENGTH = 3072 , PRIME_LENGTH_MULTIPLE = 1024 }
	DSA prime length. More...

Public Types inherited from DL_GroupParameters_IntegerBasedImpl< ModExpPrecomputation >
typedef GROUP_PRECOMP::Element	Element

Public Types inherited from DL_GroupParametersImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element >, DL_GroupParameters_IntegerBased >
typedef ModExpPrecomputation	GroupPrecomputation

typedef GROUP_PRECOMP::Element	Element

typedef DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element >	BasePrecomputation

Public Types inherited from DL_GroupParameters< Integer >
typedef Integer	Element

Public Member Functions
bool	ValidateGroup (RandomNumberGenerator &rng, unsigned int level) const
	Check the group for errors. More...

void	GenerateRandom (RandomNumberGenerator &rng, const NameValuePairs &alg)
	Generate a random key or crypto parameters. More...

Public Member Functions inherited from DL_GroupParameters_GFP
bool	IsIdentity (const Integer &element) const
	Determines if an element is an identity. More...

void	SimultaneousExponentiate (Element results, const Element &base, const Integer exponents, unsigned int exponentsCount) const
	Exponentiates a base to multiple exponents. More...

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

Element	MultiplyElements (const Element &a, const Element &b) const

Element	CascadeExponentiate (const Element &element1, const Integer &exponent1, const Element &element2, const Integer &exponent2) const

Public Member Functions inherited from DL_GroupParameters_IntegerBasedImpl< ModExpPrecomputation >
bool	GetVoidValue (const char name, const std::type_info &valueType, void pValue) const
	Get a named value. More...

void	AssignFrom (const NameValuePairs &source)
	Initialize or reinitialize this key. More...

const DL_FixedBasePrecomputation< Element > &	GetBasePrecomputation () const
	Retrieves the group precomputation. More...

DL_FixedBasePrecomputation< Element > &	AccessBasePrecomputation ()
	Retrieves the group precomputation. More...

const Integer &	GetModulus () const
	Retrieve the modulus for the group. More...

const Integer &	GetGenerator () const
	Retrieves a reference to the group generator. More...

void	SetModulusAndSubgroupGenerator (const Integer &p, const Integer &g)
	Set group parameters. More...

bool	operator== (const DL_GroupParameters_IntegerBasedImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element > > &rhs) const

bool	operator!= (const DL_GroupParameters_IntegerBasedImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element > > &rhs) const

Public Member Functions inherited from DL_GroupParametersImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename GROUP_PRECOMP::Element >, DL_GroupParameters_IntegerBased >
const DL_GroupPrecomputation< Element > &	GetGroupPrecomputation () const
	Retrieves the group precomputation. More...

const DL_FixedBasePrecomputation< Element > &	GetBasePrecomputation () const
	Retrieves the group precomputation. More...

DL_FixedBasePrecomputation< Element > &	AccessBasePrecomputation ()
	Retrieves the group precomputation. More...

Public Member Functions inherited from DL_GroupParameters_IntegerBased
void	Initialize (const DL_GroupParameters_IntegerBased &params)
	Initialize a group parameters over integers. More...

void	Initialize (RandomNumberGenerator &rng, unsigned int pbits)
	Create a group parameters over integers. More...

void	Initialize (const Integer &p, const Integer &g)
	Initialize a group parameters over integers. More...

void	Initialize (const Integer &p, const Integer &q, const Integer &g)
	Initialize a group parameters over integers. More...

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

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

void	GenerateRandom (RandomNumberGenerator &rng, const NameValuePairs &alg)
	Generate a random key. More...

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

void	AssignFrom (const NameValuePairs &source)
	Initialize or reinitialize this key. More...

const Integer &	GetSubgroupOrder () const
	Retrieves the subgroup order. More...

Integer	GetGroupOrder () const
	Retrieves the order of the group. More...

bool	ValidateGroup (RandomNumberGenerator &rng, unsigned int level) const
	Check the group for errors. More...

bool	ValidateElement (unsigned int level, const Integer &element, const DL_FixedBasePrecomputation< Integer > *precomp) const
	Check the element for errors. More...

bool	FastSubgroupCheckAvailable () const
	Determine if subgroup membership check is fast. More...

void	EncodeElement (bool reversible, const Element &element, byte *encoded) const
	Encodes the element. More...

unsigned int	GetEncodedElementSize (bool reversible) const
	Retrieve the encoded element's size. More...

Integer	DecodeElement (const byte *encoded, bool checkForGroupMembership) const
	Decodes the element. More...

Integer	ConvertElementToInteger (const Element &element) const
	Converts an element to an Integer. More...

Integer	GetMaxExponent () const
	Retrieve the maximum exponent for the group. More...

OID	GetAlgorithmID () const
	Retrieve the OID of the algorithm. More...

virtual const Integer &	GetModulus () const =0
	Retrieve the modulus for the group. More...

virtual void	SetModulusAndSubgroupGenerator (const Integer &p, const Integer &g)=0
	Set group parameters. More...

void	SetSubgroupOrder (const Integer &q)
	Set subgroup order. More...

Public Member Functions inherited from ASN1CryptoMaterial< DL_GroupParameters< Integer > >
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 void	BERDecode (BufferedTransformation &bt)=0
	Decode this object from a BufferedTransformation. More...

virtual void	DEREncode (BufferedTransformation &bt) const =0
	Encode this object into a BufferedTransformation. More...

virtual void	BEREncode (BufferedTransformation &bt) const
	Encode this object into a BufferedTransformation. More...

Public Member Functions inherited from DL_GroupParameters< Integer >
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...

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

void	Precompute (unsigned int precomputationStorage=16)
	Perform precomputation. More...

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

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

virtual const Element &	GetSubgroupGenerator () const
	Retrieves the subgroup generator. More...

virtual void	SetSubgroupGenerator (const Element &base)
	Sets the subgroup generator. More...

virtual Element	ExponentiateBase (const Integer &exponent) const
	Exponentiates the base. More...

virtual Element	ExponentiateElement (const Element &base, const Integer &exponent) const
	Exponentiates an element. More...

virtual const DL_GroupPrecomputation< Element > &	GetGroupPrecomputation () const=0
	Retrieves the group precomputation. More...

virtual const DL_FixedBasePrecomputation< Element > &	GetBasePrecomputation () const=0
	Retrieves the group precomputation. More...

virtual DL_FixedBasePrecomputation< Element > &	AccessBasePrecomputation ()=0
	Retrieves the group precomputation. More...

virtual const Integer &	GetSubgroupOrder () const=0
	Retrieves the subgroup order. More...

virtual Integer	GetMaxExponent () const=0
	Retrieves the maximum exponent for the group. More...

virtual Integer	GetGroupOrder () const
	Retrieves the order of the group. More...

virtual Integer	GetCofactor () const
	Retrieves the cofactor. More...

virtual unsigned int	GetEncodedElementSize (bool reversible) const=0
	Retrieves the encoded element's size. More...

virtual void	EncodeElement (bool reversible, const Element &element, byte *encoded) const=0
	Encodes the element. More...

virtual Element	DecodeElement (const byte *encoded, bool checkForGroupMembership) const=0
	Decodes the element. More...

virtual Integer	ConvertElementToInteger (const Element &element) const=0
	Converts an element to an Integer. More...

virtual bool	ValidateGroup (RandomNumberGenerator &rng, unsigned int level) const=0
	Check the group for errors. More...

virtual bool	ValidateElement (unsigned int level, const Element &element, const DL_FixedBasePrecomputation< Element > *precomp) const=0
	Check the element for errors. More...

virtual bool	FastSubgroupCheckAvailable () const=0

virtual bool	IsIdentity (const Element &element) const=0
	Determines if an element is an identity. More...

virtual void	SimultaneousExponentiate (Element results, const Element &base, const Integer exponents, unsigned int exponentsCount) const=0
	Exponentiates a base to multiple exponents. More...

Public Member Functions inherited from GeneratableCryptoMaterial
virtual void	GenerateRandom (RandomNumberGenerator &rng, const NameValuePairs &params=g_nullNameValuePairs)
	Generate a random key or crypto parameters. More...

void	GenerateRandomWithKeySize (RandomNumberGenerator &rng, unsigned int keySize)
	Generate a random key or crypto parameters. More...

Public Member Functions inherited from CryptoMaterial
virtual void	AssignFrom (const NameValuePairs &source)=0
	Assign values to this object. More...

virtual bool	Validate (RandomNumberGenerator &rng, unsigned int level) const =0
	Check this object for errors. More...

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
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...

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

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

virtual CRYPTOPP_DLL bool	GetVoidValue (const char name, const std::type_info &valueType, void pValue) const =0
	Get a named value. More...

Static Public Member Functions
static bool	IsValidPrimeLength (unsigned int pbits)
	Check the prime length for errors. More...

Static Public Member Functions inherited from DL_GroupParameters_IntegerBased
static std::string	StaticAlgorithmNamePrefix ()

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. More...

Detailed Description

DSA group parameters.

These are GF(p) group parameters that are allowed by the DSA standard

See also: DL_Keys_DSA

Since: Crypto++ 1.0

Definition at line 732 of file gfpcrypt.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

DSA prime length.

Enumerator
MIN_PRIME_LENGTH	Minimum prime length.
MAX_PRIME_LENGTH	Maximum prime length.
PRIME_LENGTH_MULTIPLE	Prime length multiple.

Definition at line 778 of file gfpcrypt.h.

Constructor & Destructor Documentation

◆ ~DL_GroupParameters_DSA()

virtual DL_GroupParameters_DSA::~DL_GroupParameters_DSA ( )

inlinevirtual

Definition at line 735 of file gfpcrypt.h.

Member Function Documentation

◆ ValidateGroup()

bool DL_GroupParameters_DSA::ValidateGroup	(	RandomNumberGenerator &	rng,
		unsigned int	level
	)		const

virtual

Check the group for errors.

Parameters

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

Returns: true if the tests succeed, false otherwise

ValidateGroup() also checks that the lengths of p and q are allowed by the DSA standard.

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.

Reimplemented from DL_GroupParameters_IntegerBased.

◆ GenerateRandom()

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

virtual

Generate a random key or crypto parameters.

Parameters

rng	a RandomNumberGenerator to produce keying material
alg	additional initialization parameters

NameValuePairs can be ModulusSize alone; or Modulus, SubgroupOrder, and SubgroupGenerator. ModulusSize must be between DSA::MIN_PRIME_LENGTH and DSA::MAX_PRIME_LENGTH, and divisible by DSA::PRIME_LENGTH_MULTIPLE.

An example of changing the modulus size using NameValuePairs is shown below.

 AlgorithmParameters params = MakeParameters
   (Name::ModulusSize(), 2048);

 DL_GroupParameters_DSA groupParams;
 groupParams.GenerateRandom(prng, params);

Exceptions

KeyingErr if a key can't be generated or algorithm parameters are invalid.

Reimplemented from DL_GroupParameters_IntegerBased.

◆ IsValidPrimeLength()

static bool DL_GroupParameters_DSA::IsValidPrimeLength ( unsigned int pbits )

inlinestatic

Check the prime length for errors.

Parameters

pbits number of bits in the prime number

Returns: true if the tests succeed, false otherwise

Definition at line 774 of file gfpcrypt.h.

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

gfpcrypt.h

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ ~DL_GroupParameters_DSA()

Member Function Documentation

◆ ValidateGroup()

◆ GenerateRandom()

◆ IsValidPrimeLength()