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Class java.security.KeyGenerator

java.lang.Object
   |
   +----java.security.KeyGenerator

public abstract class KeyGenerator
extends 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: 1.2 $

Author:
David Hopwood, Raif S. Naffah

Constructor Index

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

Method Index

 o clone()
Returns a clone of this key generator.
 o engineGetParameter(String)
SPI: Gets the value of the specified algorithm parameter.
 o engineSetParameter(String, Object)
SPI: Sets the specified algorithm parameter to the specified value.
 o generateKey()
Generates a key.
 o getAlgorithm()
Returns the standard name of the algorithm for this key generator.
 o getAlgorithms()
Gets the standard names of all KeyGenerators implemented by any installed provider.
 o getAlgorithms(Provider)
Gets the standard names of all KeyGenerators implemented by a provider.
 o getInstance(String)
Generates a KeyGenerator object that implements the algorithm requested, as available in the environment.
 o getInstance(String, String)
Generates a KeyGenerator object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider.
 o getParameter(String)
Gets the value of the specified algorithm parameter.
 o initialize(SecureRandom)
Initializes the key generator.
 o setParameter(String, Object)
Sets the specified algorithm parameter to the specified value.
 o toString()

Constructors

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

Parameters:
algorithm - the standard string name of the algorithm.
Throws: NullPointerException
if algorithm == null

Methods

 o 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.
Throws: NoSuchAlgorithmException
if the algorithm is not available in the environment.
 o 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.
Throws: NoSuchAlgorithmException
if the algorithm is not available from the provider.
Throws: NoSuchProviderException
if the provider is not available in the environment.
 o getAlgorithm
 public 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.
 o initialize
 public abstract void initialize(SecureRandom random)
Initializes the key generator.

Parameters:
random - a source of randomness for this generator.
 o generateKey
 public abstract SecretKey generateKey()
Generates a key. This method generates a new key every time it is called.

Returns:
the new key.
 o 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.

Parameters:
param - the string identifier of the parameter.
value - the parameter value.
Throws: NullPointerException
if param == null
Throws: NoSuchParameterException
if there is no parameter with name param for this key generator implementation.
Throws: InvalidParameterException
if the parameter exists but cannot be set.
Throws: InvalidParameterTypeException
if value is the wrong type for this parameter.
 o 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.

Parameters:
param - the string name of the parameter.
Returns:
the object that represents the parameter value.
Throws: NullPointerException
if param == null
Throws: NoSuchParameterException
if there is no parameter with name param for this key generator implementation.
Throws: InvalidParameterException
if the parameter exists but cannot be read.
 o 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.
Throws: InvalidParameterException
if the parameter exists but cannot be set.
Throws: InvalidParameterTypeException
if value is the wrong type for this parameter.
 o 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.
Throws: InvalidParameterException
if the parameter exists but cannot be read.
 o 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.

Throws: CloneNotSupportedException
if the key generator is not cloneable.
Overrides:
clone in class Object
 o toString
 public String toString()
Overrides:
toString in class Object
 o getAlgorithms
 public static String[] getAlgorithms(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.

 o getAlgorithms
 public static 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.


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