233 lines
6.8 KiB
Java
233 lines
6.8 KiB
Java
/* KeyFactory.java --- Key Factory Class
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Copyright (C) 1999 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.security;
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import java.security.spec.KeySpec;
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import java.security.spec.InvalidKeySpecException;
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/**
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Key factories are used to convert keys (opaque cryptographic
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keys of type Key) into key specifications (transparent
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representations of the underlying key material).
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Key factories are bi-directional. They allow a key class
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to be converted into a key specification (key material) and
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back again.
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For example DSA public keys can be specified as
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DSAPublicKeySpec or X509EncodedKeySpec. The key factory
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translate these key specifications.
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@since JDK 1.2
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@author Mark Benvenuto
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*/
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public class KeyFactory
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{
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private KeyFactorySpi keyFacSpi;
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private Provider provider;
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private String algorithm;
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/**
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Constructs a new keyFactory with the specified parameters.
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@param keyFacSpi Key Factory SPI to use
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@param provider the provider of the Key Factory SPI
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@param algorithm the name of the key algorithm for this key factory
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*/
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protected KeyFactory(KeyFactorySpi keyFacSpi, Provider provider,
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String algorithm)
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{
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this.keyFacSpi = keyFacSpi;
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this.provider = provider;
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this.algorithm = algorithm;
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}
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/**
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Gets an instance of the KeyFactory class representing
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the specified key factory. If the algorithm is not
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found then, it throws NoSuchAlgorithmException.
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@param algorithm the name of algorithm to choose
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@return a KeyFactory repesenting the desired algorithm
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@throws NoSuchAlgorithmException if the algorithm is not implemented by providers
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*/
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public static KeyFactory getInstance(String algorithm)
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throws NoSuchAlgorithmException
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{
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Provider[] p = Security.getProviders();
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for (int i = 0; i < p.length; i++)
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{
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String classname = p[i].getProperty("KeyFactory." + algorithm);
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if (classname != null)
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return getInstance(classname, algorithm, p[i]);
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}
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throw new NoSuchAlgorithmException(algorithm);
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}
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/**
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Gets an instance of the KeyFactory class representing
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the specified key factory from the specified provider.
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If the algorithm is not found then, it throws
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NoSuchAlgorithmException. If the provider is not found, then
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it throws NoSuchProviderException.
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@param algorithm the name of algorithm to choose
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@param provider the name of the provider to find the algorithm in
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@return a KeyFactory repesenting the desired algorithm
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@throws NoSuchAlgorithmException if the algorithm is not implemented by the provider
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@throws NoSuchProviderException if the provider is not found
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*/
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public static KeyFactory getInstance(String algorithm, String provider)
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throws NoSuchAlgorithmException, NoSuchProviderException
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{
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Provider p = Security.getProvider(provider);
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if (p == null)
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throw new NoSuchProviderException();
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return getInstance(p.getProperty("KeyFactory." + algorithm),
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algorithm, p);
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}
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private static KeyFactory getInstance(String classname,
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String algorithm,
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Provider provider)
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throws NoSuchAlgorithmException
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{
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try
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{
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return new KeyFactory((KeyFactorySpi) Class.forName(classname).
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newInstance(), provider, algorithm);
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}
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catch (ClassNotFoundException cnfe)
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{
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throw new NoSuchAlgorithmException("Class not found");
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}
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catch (InstantiationException ie)
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{
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throw new NoSuchAlgorithmException("Class instantiation failed");
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}
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catch (IllegalAccessException iae)
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{
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throw new NoSuchAlgorithmException("Illegal Access");
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}
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}
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/**
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Gets the provider that the class is from.
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@return the provider of this class
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*/
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public final Provider getProvider()
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{
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return provider;
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}
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/**
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Returns the name of the algorithm used
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@return A string with the name of the algorithm
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*/
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public final String getAlgorithm()
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{
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return algorithm;
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}
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/**
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Generates a public key from the provided key specification.
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@param keySpec key specification
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@return the public key
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@throws InvalidKeySpecException invalid key specification for
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this key factory to produce a public key
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*/
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public final PublicKey generatePublic(KeySpec keySpec) throws
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InvalidKeySpecException
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{
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return keyFacSpi.engineGeneratePublic(keySpec);
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}
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/**
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Generates a private key from the provided key specification.
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@param keySpec key specification
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@return the private key
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@throws InvalidKeySpecException invalid key specification for
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this key factory to produce a private key
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*/
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public final PrivateKey generatePrivate(KeySpec keySpec) throws
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InvalidKeySpecException
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{
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return keyFacSpi.engineGeneratePrivate(keySpec);
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}
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/**
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Returns a key specification for the given key. keySpec
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identifies the specification class to return the key
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material in.
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@param key the key
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@param keySpec the specification class to return the
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key material in.
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@return the key specification in an instance of the requested
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specification class
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@throws InvalidKeySpecException the requested key specification
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is inappropriate for this key or the key is
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unrecognized.
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*/
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public final KeySpec getKeySpec(Key key, Class keySpec)
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throws InvalidKeySpecException
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{
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return keyFacSpi.engineGetKeySpec(key, keySpec);
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}
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/**
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Translates the key from an unknown or untrusted provider
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into a key for this key factory.
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@param the key from an unknown or untrusted provider
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@return the translated key
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@throws InvalidKeySpecException if the key cannot be
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processed by this key factory
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*/
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public final Key translateKey(Key key) throws InvalidKeyException
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{
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return keyFacSpi.engineTranslateKey(key);
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}
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}
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