AlgorithmParameterGenerator JDK 1.6)

Description

public class AlgorithmParameterGenerator

The AlgorithmParameterGenerator class is used to generate a set of parameters to be used with a certain algorithm.

The AlgorithmParameterGenerator class is used to generate a set of parameters to be used with a certain algorithm. Parameter generators are constructed using the getInstance factory methods (static methods that return instances of a given class).

The object that will generate the parameters can be initialized in two different ways: in an algorithm-independent manner, or in an algorithm-specific manner:

The algorithm-independent approach uses the fact that all parameter generators share the concept of a "size" and a source of randomness. The measure of size is universally shared by all algorithm parameters, though it is interpreted differently for different algorithms. For example, in the case of parameters for the DSA algorithm, "size" corresponds to the size of the prime modulus (in bits). When using this approach, algorithm-specific parameter generation values - if any - default to some standard values, unless they can be derived from the specified size.
The other approach initializes a parameter generator object using algorithm-specific semantics, which are represented by a set of algorithm-specific parameter generation values. To generate Diffie-Hellman system parameters, for example, the parameter generation values usually consist of the size of the prime modulus and the size of the random exponent, both specified in number of bits.

In case the client does not explicitly initialize the AlgorithmParameterGenerator (via a call to an init method), each provider must supply (and document) a default initialization. For example, the Sun provider uses a default modulus prime size of 1024 bits for the generation of DSA parameters.

See also: AlgorithmParameters AlgorithmParameterSpec

Methods

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publicfinal AlgorithmParameters generateParameters ()

Generates the parameters.

publicfinal String getAlgorithm ()

Returns the standard name of the algorithm this parameter generator is associated with.

publicstatic AlgorithmParameterGenerator getInstance (String algorithm) throws NoSuchAlgorithmException

Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.

publicstatic AlgorithmParameterGenerator getInstance (String algorithm, Provider provider) throws NoSuchAlgorithmException

Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.

publicstatic AlgorithmParameterGenerator getInstance (String algorithm, String provider) throws NoSuchAlgorithmException NoSuchProviderException

Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.

publicfinal Provider getProvider ()

Returns the provider of this algorithm parameter generator object.

publicfinal void init (AlgorithmParameterSpec genParamSpec) throws InvalidAlgorithmParameterException

Initializes this parameter generator with a set of algorithm-specific parameter generation values.

Initializes this parameter generator with a set of algorithm-specific
parameter generation values.
To generate the parameters, the SecureRandom
implementation of the highest-priority installed provider is used as
the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness is
used.)
Parameters:
- genParamSpec - the set of algorithm-specific parameter generation values.
Throws:
- InvalidAlgorithmParameterException - if the given parameter generation values are inappropriate for this parameter generator.

publicfinal void init (AlgorithmParameterSpec genParamSpec, SecureRandom random) throws InvalidAlgorithmParameterException

Initializes this parameter generator with a set of algorithm-specific parameter generation values.

publicfinal void init (int size)

Initializes this parameter generator for a certain size.

Initializes this parameter generator for a certain size.
To create the parameters, the SecureRandom
implementation of the highest-priority installed provider is used as
the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness is
used.)
Parameters:
- size - the size (number of bits).

publicfinal void init (int size, SecureRandom random)

Initializes this parameter generator for a certain size and source of randomness.