iaik.security.dsa

Class DSAKeyPairGenerator

java.lang.Object

java.security.KeyPairGeneratorSpi

java.security.KeyPairGenerator

iaik.security.dsa.DSAKeyPairGenerator

All Implemented Interfaces:

java.security.interfaces.DSAKeyPairGenerator

Direct Known Subclasses:

SHA1withDSAKeyPairGenerator, SHA224withDSAKeyPairGenerator, SHA256withDSAKeyPairGenerator

public class DSAKeyPairGenerator
extends java.security.KeyPairGenerator
implements java.security.interfaces.DSAKeyPairGenerator

Key pair generator for DSA keys as specified in FIPS PUB 186.

Valid length for the modulus is any multiple of 64 in the range of 512 to 1024, 2048 or 3072. If the modulus length is greater than 3072 a SHA2withDSAKeyPairGenerator is used.

This class contains precalculated public DSA parameters for modulus lengths of 512, 768, 1024 bits, and 2048 and 3072 bits (by SHA2withDSAKeyPairGenerator).

To create a DSA key pair, a KeyPairGenerator has to be instantiated, properly initialized and directed to actually generate the keys by calling the generateKeyPair() method. If the generator is not initialized by explicitly calling an initialize method, the modulus length is set to 2048 bits.

Generating DSA keys using a modulus length of, e.g. 1024 bits (explicitly initialized), may be done by:

 KeyPairGenerator key_gen = KeyPairGenerator.getIntance("DSA", "IAIK");
 key_gen.initialize(1024);
 KeyPair key_pair = key_gen.generateKeyPair();
 

Version:

File Revision 23

See Also:

KeyPairGenerator, KeyPair, DSA, RawDSA, DSAPublicKey, DSAPrivateKey, DSAKeyFactory, DSAParams

Constructor Summary

Constructors

Constructor and Description
DSAKeyPairGenerator() Default constructor for creating a DSAKeyPairGenerator object.
DSAKeyPairGenerator(java.lang.String name) Creates a DSAKeyPairGenerator with the given name.

Method Summary

Methods

Modifier and Type	Method and Description
java.security.KeyPair	generateKeyPair() Actually generates the requested KeyPair.
void	initialize(java.security.spec.AlgorithmParameterSpec params, java.security.SecureRandom random) Initializes this DSAKeyPairGenerator with given DSAParameterSpec and random seed.
void	initialize(java.security.interfaces.DSAParams params, java.security.SecureRandom random) Initializes this DSAKeyPairGenerator with given DSA parameters and random seed.
void	initialize(int strength) Initializes this DSAKeyPairGenerator for given prime modulus length.
void	initialize(int modlen, boolean genParams, java.security.SecureRandom random) Initializes this DSAKeyPairGenerator for given modulus length with the given random seed.
void	initialize(int strength, java.security.SecureRandom random) Initializes this DSAKeyPairGenerator for given modulus length with the given random seed.

Methods inherited from class java.security.KeyPairGenerator

genKeyPair, getAlgorithm, getInstance, getInstance, getInstance, getProvider, initialize

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DSAKeyPairGenerator

public DSAKeyPairGenerator()

Default constructor for creating a DSAKeyPairGenerator object.

DSAKeyPairGenerator

public DSAKeyPairGenerator(java.lang.String name)

Creates a DSAKeyPairGenerator with the given name.

Parameters:

name - the name of the KeyPairGenerator

Method Detail

initialize

public void initialize(int strength)

Initializes this DSAKeyPairGenerator for given prime modulus length.

Overrides:

initialize in class java.security.KeyPairGenerator

Parameters:

strength - the length of the modulus (any multiple of 64 in the range of 512 to 1024, or 2048 or 3072)

initialize

public void initialize(int strength,
              java.security.SecureRandom random)

Initializes this DSAKeyPairGenerator for given modulus length with the given random seed.

Overrides:

initialize in class java.security.KeyPairGenerator

Parameters:

strength - the length of the modulus (any multiple of 64 in the range of 512 to 1024, or 2048 or 3072)

random - the random seed as SecureRandom

initialize

public void initialize(int modlen,
              boolean genParams,
              java.security.SecureRandom random)
                throws java.security.InvalidParameterException

Initializes this DSAKeyPairGenerator for given modulus length with the given random seed. This method initializes the generator either with precomputed DSA parameter values p, q and g (when genParams is set to false), or by generating new DSA parameter values (when genParams is set to true). Precomputed parameters are available for modulus length of either 512, 768, 1024 bits, or 2048 or 3072 bits).

Specified by:

initialize in interface java.security.interfaces.DSAKeyPairGenerator

Parameters:

modlen - the length of the modulus in bits (512, 768, or 1024, 2048 or 3072)

genParams - true for generating new parameters, false for using precomputed values for p, q and g

random - the random seed as SecureRandom

Throws:

java.security.InvalidParameterException - if the given modulus length is not a multiple of 64 between 512 and 1024, or 2048 or 3072

initialize

public void initialize(java.security.interfaces.DSAParams params,
              java.security.SecureRandom random)
                throws java.security.InvalidParameterException

Initializes this DSAKeyPairGenerator with given DSA parameters and random seed.

Specified by:

initialize in interface java.security.interfaces.DSAKeyPairGenerator

Parameters:

params - the DSAParams representing prime p, sub-prime q, and base g

random - the random seed as SecureRandom

Throws:

java.security.InvalidParameterException - if the given parameters to not match to DSAParams

initialize

public void initialize(java.security.spec.AlgorithmParameterSpec params,
              java.security.SecureRandom random)
                throws java.security.InvalidAlgorithmParameterException

Initializes this DSAKeyPairGenerator with given DSAParameterSpec and random seed.

Overrides:

initialize in class java.security.KeyPairGenerator

Parameters:

params - the DSAParamaterSpec representing p, q and g for initializing this generator

random - the random seed as SecureRandom

Throws:

java.security.InvalidAlgorithmParameterException - if the given parameter specification is not a DSAParameterSpec

generateKeyPair

public java.security.KeyPair generateKeyPair()

Actually generates the requested KeyPair.

Overrides:

generateKeyPair in class java.security.KeyPairGenerator

Returns:

the requested key pair