xjava.security

Class KeyGenerator

Implemented Interfaces:
Parameterized
Known Direct 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 $

Authors:
David Hopwood
Raif S. Naffah

Since:
IJCE 1.0.0

Constructor Summary

KeyGenerator(String algorithm)
Creates a KeyGenerator object for the specified algorithm.

Method Summary

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

Constructor Details

KeyGenerator

protected KeyGenerator(String algorithm)
Creates a KeyGenerator object for the specified algorithm.

Parameters:
algorithm - the standard string name of the algorithm.

Method Details

clone

public Object clone()
            throws 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.


engineGetParameter

protected Object engineGetParameter(String param)
            throws NoSuchParameterException,
                   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.


engineSetParameter

protected void engineSetParameter(String param,
                                  Object value)
            throws NoSuchParameterException,
                   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.
InvalidParameterTypeException - if value is the wrong type for this parameter.


generateKey

public SecretKey generateKey()
Generates a key. This method generates a new key every time it is called.

Returns:
the new key.


getAlgorithm

public String getAlgorithm()

Returns:
the standard string name of the algorithm.


getAlgorithms

public static String[] getAlgorithms()

Since:
IJCE 1.0.1


getAlgorithms

public static String[] getAlgorithms(Provider provider)

Since:
IJCE 1.0.1


getInstance

public static KeyGenerator getInstance(String algorithm)
            throws 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.


getInstance

public static KeyGenerator getInstance(String algorithm,
                                       String provider)
            throws NoSuchAlgorithmException,
                   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.


getParameter

public Object getParameter(String param)
            throws NoSuchParameterException,
                   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:
NoSuchParameterException - if there is no parameter with name param for this key generator implementation.


initialize

public void initialize(SecureRandom random)
Initializes the key generator.

Parameters:
random - a source of randomness for this generator.


setParameter

public void setParameter(String param,
                         Object value)
            throws NoSuchParameterException,
                   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:
NoSuchParameterException - if there is no parameter with name param for this key generator implementation.
InvalidParameterTypeException - if value is the wrong type for this parameter.


toString

public String toString()