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java.security

Class KeyFactory

public class KeyFactory
extends Object
Key factories are used to convert keys (opaque cryptographic keys of type Key) into key specifications (transparent representations of the underlying key material).

Key factories are bi-directional. They allow a key class to be converted into a key specification (key material) and back again. For example DSA public keys can be specified as DSAPublicKeySpec or X509EncodedKeySpec. A key factory translates these key specifications.

Since:
1.2
See Also:
Key, KeySpec, DSAPublicKeySpec, X509EncodedKeySpec

Constructor Summary

KeyFactory(KeyFactorySpi keyFacSpi, Provider provider, String algorithm)
Constructs a new instance of KeyFactory with the specified parameters.

Method Summary

extends KeySpec> T getKeySpec(Key key, Class keySpec)
Returns a key specification for the given key.
PrivateKey
generatePrivate(KeySpec keySpec)
Generates a private key from the provided key specification.
PublicKey
generatePublic(KeySpec keySpec)
Generates a public key from the provided key specification.
String
getAlgorithm()
Returns the name of the algorithm used.
static KeyFactory
getInstance(String algorithm)
Returns a new instance of KeyFactory representing the specified key factory.
static KeyFactory
getInstance(String algorithm, String provider)
Returns a new instance of KeyFactory representing the specified key factory from the specified provider.
static KeyFactory
getInstance(String algorithm, Provider provider)
Returns a new instance of KeyFactory representing the specified key factory from the designated Provider.
Provider
getProvider()
Returns the Provider of this instance.
Key
translateKey(Key key)
Translates the key from an unknown or untrusted provider into a key from this key factory.

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

KeyFactory

protected KeyFactory(KeyFactorySpi keyFacSpi,
                     Provider provider,
                     String algorithm)
Constructs a new instance of KeyFactory with the specified parameters.
Parameters:
keyFacSpi - the key factory to use.
provider - the provider to use.
algorithm - the name of the key algorithm to use.

Method Details

extends KeySpec> T getKeySpec

public final extends KeySpec> T getKeySpec(Key key,
                                              Class keySpec)
            throws InvalidKeySpecException
Returns a key specification for the given key. keySpec identifies the specification class to return the key material in.
Parameters:
key - the key to use.
keySpec - the specification class to use.
Returns:
the key specification in an instance of the requested specification class.
Throws:
InvalidKeySpecException - the requested key specification is inappropriate for this key or the key is unrecognized.

generatePrivate

public final PrivateKey generatePrivate(KeySpec keySpec)
            throws InvalidKeySpecException
Generates a private key from the provided key specification.
Parameters:
keySpec - the key specification.
Returns:
the private key.
Throws:
InvalidKeySpecException - if the key specification is invalid.

generatePublic

public final PublicKey generatePublic(KeySpec keySpec)
            throws InvalidKeySpecException
Generates a public key from the provided key specification.
Parameters:
keySpec - the key specification.
Returns:
the public key.
Throws:
InvalidKeySpecException - if the key specification is invalid.

getAlgorithm

public final String getAlgorithm()
Returns the name of the algorithm used.
Returns:
the name of the algorithm used.

getInstance

public static KeyFactory getInstance(String algorithm)
            throws NoSuchAlgorithmException
Returns a new instance of KeyFactory representing the specified key factory.
Parameters:
algorithm - the name of algorithm to use.
Returns:
a new instance repesenting the desired algorithm.
Throws:
NoSuchAlgorithmException - if the algorithm is not implemented by any provider.
IllegalArgumentException - if algorithm is null or is an empty string.

getInstance

public static KeyFactory getInstance(String algorithm,
                                     String provider)
            throws NoSuchAlgorithmException,
                   NoSuchProviderException
Returns a new instance of KeyFactory representing the specified key factory from the specified provider.
Parameters:
algorithm - the name of algorithm to use.
provider - the name of the provider to use.
Returns:
a new instance repesenting the desired algorithm.
Throws:
NoSuchAlgorithmException - if the algorithm is not implemented by the named provider.
NoSuchProviderException - if the named provider was not found.
IllegalArgumentException - if either algorithm or provider is null or empty.

getInstance

public static KeyFactory getInstance(String algorithm,
                                     Provider provider)
            throws NoSuchAlgorithmException
Returns a new instance of KeyFactory representing the specified key factory from the designated Provider.
Parameters:
algorithm - the name of algorithm to use.
provider - the Provider to use.
Returns:
a new instance repesenting the desired algorithm.
Throws:
NoSuchAlgorithmException - if the algorithm is not implemented by Provider.
IllegalArgumentException - if either algorithm or provider is null, or if algorithm is an empty string.
Since:
1.4
See Also:
Provider

getProvider

public final Provider getProvider()
Returns the Provider of this instance.
Returns:
the Provider of this instance.

translateKey

public final Key translateKey(Key key)
            throws InvalidKeyException
Translates the key from an unknown or untrusted provider into a key from this key factory.
Parameters:
key - the key to translate from.
Returns:
the translated key.
Throws:
InvalidKeyException - if the key cannot be processed by this key factory.
KeyFactory.java --- Key Factory Class Copyright (C) 1999, 2003, 2004 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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