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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * 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).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.security.provider;

import java.security.Key;

import java.security.PublicKey;

import java.security.PrivateKey;

import java.security.KeyFactorySpi;

import java.security.InvalidKeyException;

import java.security.interfaces.DSAParams;

import java.security.spec.DSAPublicKeySpec;

import java.security.spec.DSAPrivateKeySpec;

import java.security.spec.KeySpec;

import java.security.spec.InvalidKeySpecException;

import java.security.spec.X509EncodedKeySpec;

import java.security.spec.PKCS8EncodedKeySpec;

/**

 * This class implements the DSA key factory of the Sun provider.

 *

 * @author Jan Luehe

 *

 *

 * @since 1.2

 */

public class DSAKeyFactory extends 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 PublicKey engineGeneratePublic(KeySpec keySpec)

    throws InvalidKeySpecException {

        try {

            if (keySpec instanceof DSAPublicKeySpec) {

                DSAPublicKeySpec dsaPubKeySpec = (DSAPublicKeySpec)keySpec;

            } else if (keySpec instanceof X509EncodedKeySpec) {

            } else {

                throw new InvalidKeySpecException

                    ("Inappropriate key specification");

            }

        } catch (InvalidKeyException e) {

            throw new InvalidKeySpecException

                ("Inappropriate key specification: " + e.getMessage());

        }

    }

    /**

     * 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 PrivateKey engineGeneratePrivate(KeySpec keySpec)

    throws InvalidKeySpecException {

        try {

            if (keySpec instanceof DSAPrivateKeySpec) {

                DSAPrivateKeySpec dsaPrivKeySpec = (DSAPrivateKeySpec)keySpec;

                return new DSAPrivateKey(dsaPrivKeySpec.getX(),

                                         dsaPrivKeySpec.getP(),

                                         dsaPrivKeySpec.getQ(),

                                         dsaPrivKeySpec.getG());

            } else if (keySpec instanceof PKCS8EncodedKeySpec) {

                return new DSAPrivateKey

                    (((PKCS8EncodedKeySpec)keySpec).getEncoded());

            } else {

                throw new InvalidKeySpecException

                    ("Inappropriate key specification");

            }

        } catch (InvalidKeyException e) {

            throw new InvalidKeySpecException

                ("Inappropriate key specification: " + e.getMessage());

        }

    }

    /**

     * Returns a specification (key material) of the given key object

     * in the requested format.

     *

     * @param key the key

     *

     * @param keySpec the requested format in which the key material shall be

     * returned

     *

     * @return the underlying key specification (key material) in the

     * requested format

     *

     * @exception InvalidKeySpecException if the requested key specification is

     * inappropriate for the given key, or the given key cannot be processed

     * (e.g., the given key has an unrecognized algorithm or format).

     */

    protected <T extends KeySpec>

        T engineGetKeySpec(Key key, Class<T> keySpec)

    throws InvalidKeySpecException {

        DSAParams params;

        try {

            if (key instanceof java.security.interfaces.DSAPublicKey) {

                // Determine valid key specs

                Class<?> dsaPubKeySpec = Class.forName

                    ("java.security.spec.DSAPublicKeySpec");

                Class<?> x509KeySpec = Class.forName

                    ("java.security.spec.X509EncodedKeySpec");

                if (dsaPubKeySpec.isAssignableFrom(keySpec)) {

                    java.security.interfaces.DSAPublicKey dsaPubKey

                        = (java.security.interfaces.DSAPublicKey)key;

                    params = dsaPubKey.getParams();

                    return keySpec.cast(new DSAPublicKeySpec(dsaPubKey.getY(),

                                                             params.getP(),

                                                             params.getQ(),

                                                             params.getG()));

                } else if (x509KeySpec.isAssignableFrom(keySpec)) {

                    return keySpec.cast(new X509EncodedKeySpec(key.getEncoded()));

                } else {

                    throw new InvalidKeySpecException

                        ("Inappropriate key specification");

                }

            } else if (key instanceof java.security.interfaces.DSAPrivateKey) {

                // Determine valid key specs

                Class<?> dsaPrivKeySpec = Class.forName

                    ("java.security.spec.DSAPrivateKeySpec");

                Class<?> pkcs8KeySpec = Class.forName

                    ("java.security.spec.PKCS8EncodedKeySpec");

                if (dsaPrivKeySpec.isAssignableFrom(keySpec)) {

                    java.security.interfaces.DSAPrivateKey dsaPrivKey

                        = (java.security.interfaces.DSAPrivateKey)key;

                    params = dsaPrivKey.getParams();

                    return keySpec.cast(new DSAPrivateKeySpec(dsaPrivKey.getX(),

                                                              params.getP(),

                                                              params.getQ(),

                                                              params.getG()));

                } else if (pkcs8KeySpec.isAssignableFrom(keySpec)) {

                    return keySpec.cast(new PKCS8EncodedKeySpec(key.getEncoded()));

                } else {

                    throw new InvalidKeySpecException

                        ("Inappropriate key specification");

                }

            } else {

                throw new InvalidKeySpecException("Inappropriate key type");

            }

        } catch (ClassNotFoundException e) {

            throw new InvalidKeySpecException

                ("Unsupported key specification: " + e.getMessage());

        }

    }

    /**

     * 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 Key engineTranslateKey(Key key) throws InvalidKeyException {

        try {

            if (key instanceof java.security.interfaces.DSAPublicKey) {

                // Check if key originates from this factory

                if (key instanceof sun.security.provider.DSAPublicKey) {

                    return key;

                }

                // Convert key to spec

                DSAPublicKeySpec dsaPubKeySpec

                    = engineGetKeySpec(key, DSAPublicKeySpec.class);

                // Create key from spec, and return it

                return engineGeneratePublic(dsaPubKeySpec);

            } else if (key instanceof java.security.interfaces.DSAPrivateKey) {

                // Check if key originates from this factory

                if (key instanceof sun.security.provider.DSAPrivateKey) {

                    return key;

                }

                // Convert key to spec

                DSAPrivateKeySpec dsaPrivKeySpec

                    = engineGetKeySpec(key, DSAPrivateKeySpec.class);

                // Create key from spec, and return it

                return engineGeneratePrivate(dsaPrivKeySpec);

            } else {

                throw new InvalidKeyException("Wrong algorithm type");

            }

        } catch (InvalidKeySpecException e) {

            throw new InvalidKeyException("Cannot translate key: "

                                          + e.getMessage());

        }

    }

}