xjava.security

Class KeyGenerator

java.lang.Object

xjava.security.KeyGenerator

All Implemented Interfaces:

Parameterized

Direct Known Subclasses:

RawKeyGenerator

public abstract class KeyGenerator
extends java.lang.Object
implements Parameterized

The KeyGenerator class is used to generate keys for a given algorithm. Key generators are constructed using the getInstance factory methods (static methods that return instances of a given class).

The KeyGenerator interface is entirely algorithm independent, and, as for the KeyPairGenerator instances, KeyGenerator instances may be cast to algorithm-specific interfaces defined elsewhere in the Java Cryptography Architecture.

A typical set of calls would be:

    import java.security.KeyGenerator;
 

    SecureRandom random = new SecureRandom();
    KeyGenerator keygen = KeyGenerator.getInstance("DES");
    keygen.initialize(random);
    Key key = keygen.generateKey();
 

Copyright © 1997 Systemics Ltd on behalf of the Cryptix Development Team.
All rights reserved.

$Revision: 1.3 $

Since:

IJCE 1.0.0

Author:

David Hopwood, Raif S. Naffah

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	KeyGenerator(java.lang.String algorithm) Creates a KeyGenerator object for the specified algorithm.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone() Returns a clone of this key generator.
protected java.lang.Object	engineGetParameter(java.lang.String param) SPI: Gets the value of the specified algorithm parameter.
protected void	engineSetParameter(java.lang.String param, java.lang.Object value) SPI: Sets the specified algorithm parameter to the specified value.
abstract SecretKey	generateKey() Generates a key.
java.lang.String	getAlgorithm() Returns the standard name of the algorithm for this key generator.
static java.lang.String[]	getAlgorithms() Gets the standard names of all KeyGenerators implemented by any installed provider.
static java.lang.String[]	getAlgorithms(java.security.Provider provider) Gets the standard names of all KeyGenerators implemented by a provider.
static KeyGenerator	getInstance(java.lang.String algorithm) Generates a KeyGenerator object that implements the algorithm requested, as available in the environment.
static KeyGenerator	getInstance(java.lang.String algorithm, java.lang.String provider) Generates a KeyGenerator object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider.
java.lang.Object	getParameter(java.lang.String param) Gets the value of the specified algorithm parameter.
abstract void	initialize(java.security.SecureRandom random) Initializes the key generator.
void	setParameter(java.lang.String param, java.lang.Object value) Sets the specified algorithm parameter to the specified value.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyGenerator

protected KeyGenerator(java.lang.String algorithm)

Creates a KeyGenerator object for the specified algorithm.

Parameters:

algorithm - the standard string name of the algorithm.

Throws:

java.lang.NullPointerException - if algorithm == null

Method Detail

getInstance

public static KeyGenerator getInstance(java.lang.String algorithm)
                                throws java.security.NoSuchAlgorithmException

Generates a KeyGenerator object that implements the algorithm requested, as available in the environment.

See International JCE Standard Algorithm Names for a list of KeyGenerator algorithm names.

Parameters:

algorithm - the standard name or an alias for the algorithm.

Returns:

the new KeyGenerator object.

Throws:

java.security.NoSuchAlgorithmException - if the algorithm is not available in the environment.

getInstance

public static KeyGenerator getInstance(java.lang.String algorithm,
                                       java.lang.String provider)
                                throws java.security.NoSuchAlgorithmException,
                                       java.security.NoSuchProviderException

Generates a KeyGenerator object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider.

See International JCE Standard Algorithm Names for a list of KeyGenerator algorithm names.

Parameters:

algorithm - the standard name or an alias for the algorithm.

provider - the string name of the provider.

Returns:

the new KeyGenerator object.

Throws:

java.security.NoSuchAlgorithmException - if the algorithm is not available from the provider.

java.security.NoSuchProviderException - if the provider is not available in the environment.

getAlgorithm

public java.lang.String getAlgorithm()

Returns the standard name of the algorithm for this key generator.

See International JCE Standard Algorithm Names for a list of KeyGenerator algorithm names.

Returns:

the standard string name of the algorithm.

initialize

public abstract void initialize(java.security.SecureRandom random)

Initializes the key generator.

Parameters:

random - a source of randomness for this generator.

generateKey

public abstract SecretKey generateKey()

Generates a key. This method generates a new key every time it is called.

Returns:

the new key.

setParameter

public void setParameter(java.lang.String param,
                         java.lang.Object value)
                  throws NoSuchParameterException,
                         java.security.InvalidParameterException,
                         InvalidParameterTypeException

Sets the specified algorithm parameter to the specified value.

This method supplies a general-purpose mechanism through which it is possible to set the various parameters of this object. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.

This method is not supported in JavaSoft's version of JCE.

Specified by:

setParameter in interface Parameterized

Parameters:

param - the string identifier of the parameter.

value - the parameter value.

Throws:

java.lang.NullPointerException - if param == null

NoSuchParameterException - if there is no parameter with name param for this key generator implementation.

java.security.InvalidParameterException - if the parameter exists but cannot be set.

InvalidParameterTypeException - if value is the wrong type for this parameter.

getParameter

public java.lang.Object getParameter(java.lang.String param)
                              throws NoSuchParameterException,
                                     java.security.InvalidParameterException

Gets the value of the specified algorithm parameter.

This method supplies a general-purpose mechanism through which it is possible to get the various parameters of this object. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.

This method is not supported in JavaSoft's version of JCE.

Specified by:

getParameter in interface Parameterized

Parameters:

param - the string name of the parameter.

Returns:

the object that represents the parameter value.

Throws:

java.lang.NullPointerException - if param == null

NoSuchParameterException - if there is no parameter with name param for this key generator implementation.

java.security.InvalidParameterException - if the parameter exists but cannot be read.

engineSetParameter

protected void engineSetParameter(java.lang.String param,
                                  java.lang.Object value)
                           throws NoSuchParameterException,
                                  java.security.InvalidParameterException,
                                  InvalidParameterTypeException

SPI: Sets the specified algorithm parameter to the specified value.

This method supplies a general-purpose mechanism through which it is possible to set the various parameters of this object. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.

The default implementation always throws a NoSuchParameterException.

This method is not supported in JavaSoft's version of JCE.

Parameters:

param - the string name of the parameter.

value - the parameter value.

Throws:

NoSuchParameterException - if there is no parameter with name param for this key generator implementation.

java.security.InvalidParameterException - if the parameter exists but cannot be set.

InvalidParameterTypeException - if value is the wrong type for this parameter.

engineGetParameter

protected java.lang.Object engineGetParameter(java.lang.String param)
                                       throws NoSuchParameterException,
                                              java.security.InvalidParameterException

SPI: Gets the value of the specified algorithm parameter.

This method supplies a general-purpose mechanism through which it is possible to get the various parameters of this object. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.

The default implementation always throws a NoSuchParameterException.

This method is not supported in JavaSoft's version of JCE.

Parameters:

param - the string name of the parameter.

Returns:

the object that represents the parameter value.

Throws:

NoSuchParameterException - if there is no parameter with name param for this key generator implementation.

java.security.InvalidParameterException - if the parameter exists but cannot be read.

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Returns a clone of this key generator.

Note: In JavaSoft's version of JCE, KeyGenerator.clone() is protected. This is not very useful, since then an application (as opposed to the key generator implementation itself) is not able to call it.

Overrides:

clone in class java.lang.Object

Throws:

java.lang.CloneNotSupportedException - if the key generator is not cloneable.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getAlgorithms

public static java.lang.String[] getAlgorithms(java.security.Provider provider)

Gets the standard names of all KeyGenerators implemented by a provider.

This method is not supported in JavaSoft's version of JCE. For compatibility you may wish to use IJCE.getAlgorithms(provider, "KeyGenerator") instead.

Since:

IJCE 1.0.1

getAlgorithms

public static java.lang.String[] getAlgorithms()

Gets the standard names of all KeyGenerators implemented by any installed provider. Algorithm names are not duplicated if they are supported by more than one provider.

This method is not supported in JavaSoft's version of JCE. For compatibility you may wish to use IJCE.getAlgorithms("KeyGenerator") instead.

Since:

IJCE 1.0.1