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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package java.security;
import java.security.spec.KeySpec;
import java.security.spec.InvalidKeySpecException;
/**
* This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
* for the <code>KeyFactory</code> class.
* All the abstract methods in this class must be implemented by each
* cryptographic service provider who wishes to supply the implementation
* of a key factory for a particular algorithm.
*
* <P> Key factories are used to convert <I>keys</I> (opaque
* cryptographic keys of type <code>Key</code>) into <I>key specifications</I>
* (transparent representations of the underlying key material), and vice
* versa.
*
* <P> Key factories are bi-directional. That is, they allow you to build an
* opaque key object from a given key specification (key material), or to
* retrieve the underlying key material of a key object in a suitable format.
*
* <P> Multiple compatible key specifications may exist for the same key.
* For example, a DSA public key may be specified using
* <code>DSAPublicKeySpec</code> or
* <code>X509EncodedKeySpec</code>. A key factory can be used to translate
* between compatible key specifications.
*
* <P> A provider should document all the key specifications supported by its
* key factory.
*
* @author Jan Luehe
*
*
* @see KeyFactory
* @see Key
* @see PublicKey
* @see PrivateKey
* @see java.security.spec.KeySpec
* @see java.security.spec.DSAPublicKeySpec
* @see java.security.spec.X509EncodedKeySpec
*
* @since 1.2
*/
public abstract class KeyFactorySpi {
/**
* Generates a public key object from the provided key
* specification (key material).
*
* @param keySpec the specification (key material) of the public key.
*
* @return the public key.
*
* @exception InvalidKeySpecException if the given key specification
* is inappropriate for this key factory to produce a public key.
*/
protected abstract PublicKey engineGeneratePublic(KeySpec keySpec)
throws InvalidKeySpecException;
/**
* Generates a private key object from the provided key
* specification (key material).
*
* @param keySpec the specification (key material) of the private key.
*
* @return the private key.
*
* @exception InvalidKeySpecException if the given key specification
* is inappropriate for this key factory to produce a private key.
*/
protected abstract PrivateKey engineGeneratePrivate(KeySpec keySpec)
throws InvalidKeySpecException;
/**
* Returns a specification (key material) of the given key
* object.
* <code>keySpec</code> identifies the specification class in which
* the key material should be returned. It could, for example, be
* <code>DSAPublicKeySpec.class</code>, to indicate that the
* key material should be returned in an instance of the
* <code>DSAPublicKeySpec</code> class.
*
* @param key the key.
*
* @param keySpec the specification class in which
* the key material should be returned.
*
* @return the underlying key specification (key material) in an instance
* of the requested specification class.
* @exception InvalidKeySpecException if the requested key specification is
* inappropriate for the given key, or the given key cannot be dealt with
* (e.g., the given key has an unrecognized format).
*/
protected abstract <T extends KeySpec>
T engineGetKeySpec(Key key, Class<T> keySpec)
throws InvalidKeySpecException;
/**
* Translates a key object, whose provider may be unknown or
* potentially untrusted, into a corresponding key object of this key
* factory.
*
* @param key the key whose provider is unknown or untrusted.
*
* @return the translated key.
*
* @exception InvalidKeyException if the given key cannot be processed
* by this key factory.
*/
protected abstract Key engineTranslateKey(Key key)
throws InvalidKeyException;
}