DESKeyFactory.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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package com.sun.crypto.provider;

import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactorySpi;
import javax.crypto.spec.DESKeySpec;
import java.security.InvalidKeyException;
import java.security.spec.KeySpec;
import java.security.spec.InvalidKeySpecException;

/**
 * This class implements the DES key factory of the Sun provider.
 *
 * @author Jan Luehe
 *
 */

public final class DESKeyFactory extends SecretKeyFactorySpi {

    /**
     * Verify the SunJCE provider in the constructor.
     *
     * @exception SecurityException if fails to verify
     * its own integrity
     */
    public DESKeyFactory() {
        if (!SunJCE.verifySelfIntegrity(this.getClass())) {
            throw new SecurityException("The SunJCE provider may have " +
                                        "been tampered.");
        }
    }
    /**
     * Generates a <code>SecretKey</code> object from the provided key
     * specification (key material).
     *
     * @param keySpec the specification (key material) of the secret key
     *
     * @return the secret key
     *
     * @exception InvalidKeySpecException if the given key specification
     * is inappropriate for this key factory to produce a public key.
     */
    protected SecretKey engineGenerateSecret(KeySpec keySpec)
        throws InvalidKeySpecException {
        DESKey desKey = null;

        try {
            if (!(keySpec instanceof DESKeySpec)) {
                throw new InvalidKeySpecException
                    ("Inappropriate key specification");
            }
            else {
                DESKeySpec desKeySpec = (DESKeySpec)keySpec;
                desKey = new DESKey(desKeySpec.getKey());
            }
        } catch (InvalidKeyException e) {
        }
        return desKey;
    }

    /**
     * Returns a specification (key material) of the given key
     * 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 KeySpec engineGetKeySpec(SecretKey key, Class keySpec)
        throws InvalidKeySpecException {

        try {

            if ((key instanceof SecretKey)
                && (key.getAlgorithm().equalsIgnoreCase("DES"))
                && (key.getFormat().equalsIgnoreCase("RAW"))) {

                // Check if requested key spec is amongst the valid ones
                if ((keySpec != null) &&
                    DESKeySpec.class.isAssignableFrom(keySpec)) {
                    return new DESKeySpec(key.getEncoded());

                } else {
                    throw new InvalidKeySpecException
                        ("Inappropriate key specification");
                }

            } else {
                throw new InvalidKeySpecException
                    ("Inappropriate key format/algorithm");
            }

        } catch (InvalidKeyException e) {
            throw new InvalidKeySpecException("Secret key has wrong size");
        }
    }

    /**
     * Translates a <code>SecretKey</code> object, whose provider may be
     * unknown or potentially untrusted, into a corresponding
     * <code>SecretKey</code> 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 SecretKey engineTranslateKey(SecretKey key)
        throws InvalidKeyException {

        try {

            if ((key != null) &&
                (key.getAlgorithm().equalsIgnoreCase("DES")) &&
                (key.getFormat().equalsIgnoreCase("RAW"))) {

                // Check if key originates from this factory
                if (key instanceof com.sun.crypto.provider.DESKey) {
                    return key;
                }
                // Convert key to spec
                DESKeySpec desKeySpec
                    = (DESKeySpec)engineGetKeySpec(key, DESKeySpec.class);
                // Create key from spec, and return it
                return engineGenerateSecret(desKeySpec);

            } else {
                throw new InvalidKeyException
                    ("Inappropriate key format/algorithm");
            }

        } catch (InvalidKeySpecException e) {
            throw new InvalidKeyException("Cannot translate key");
        }
    }
}