Crypto++  8.2
Free C++ class library of cryptographic schemes
Public Types | Public Member Functions | Static Public Member Functions | List of all members
DL_GroupParameters_DSA Class Reference

DSA group parameters. More...

+ 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 ModExpPrecomputation ::Element Element
 
- Public Types inherited from DL_GroupParametersImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename ModExpPrecomputation ::Element >, DL_GroupParameters_IntegerBased >
typedef ModExpPrecomputation GroupPrecomputation
 
typedef ModExpPrecomputation ::Element Element
 
typedef DL_FixedBasePrecomputationImpl< typename ModExpPrecomputation ::ElementBasePrecomputation
 
- 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 IntegerGetModulus () const
 Retrieve the modulus for the group. More...
 
const IntegerGetGenerator () 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 ModExpPrecomputation ::Element > > &rhs) const
 
bool operator!= (const DL_GroupParameters_IntegerBasedImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename ModExpPrecomputation ::Element > > &rhs) const
 
- Public Member Functions inherited from DL_GroupParametersImpl< ModExpPrecomputation, DL_FixedBasePrecomputationImpl< typename ModExpPrecomputation ::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...
 
const IntegerGetSubgroupOrder () const
 Retrieves the subgroup order. More...
 
Integer GetGroupOrder () const
 Retrieves the order of the group. 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...
 
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 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 ElementGetSubgroupGenerator () 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 Integer GetCofactor () const
 Retrieves the cofactor. More...
 
virtual void EncodeElement (bool reversible, const Element &element, byte *encoded) const=0
 Encodes the element. 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
void GenerateRandomWithKeySize (RandomNumberGenerator &rng, unsigned int keySize)
 Generate a random key or crypto parameters. More...
 
- Public Member Functions inherited from CryptoMaterial
virtual void ThrowIfInvalid (RandomNumberGenerator &rng, unsigned int level) const
 Check this object for errors. 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 >
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...
 

Static Public Member Functions

static bool CRYPTOPP_API IsValidPrimeLength (unsigned int pbits)
 Check the prime length for errors. More...
 
- Static Public Member Functions inherited from DL_GroupParameters_IntegerBased
static std::string CRYPTOPP_API StaticAlgorithmNamePrefix ()
 
- 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

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 696 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 742 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
rngRandomNumberGenerator for objects which use randomized testing
levellevel 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.

Definition at line 70 of file gfpcrypt.cpp.

◆ GenerateRandom()

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

Generate a random key or crypto parameters.

Parameters
rnga RandomNumberGenerator to produce keying material
algadditional 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
KeyingErrif a key can't be generated or algorithm parameters are invalid.

Reimplemented from DL_GroupParameters_IntegerBased.

Definition at line 37 of file gfpcrypt.cpp.

◆ IsValidPrimeLength()

static bool CRYPTOPP_API DL_GroupParameters_DSA::IsValidPrimeLength ( unsigned int  pbits)
inlinestatic

Check the prime length for errors.

Parameters
pbitsnumber of bits in the prime number
Returns
true if the tests succeed, false otherwise

Definition at line 738 of file gfpcrypt.h.


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