/*

 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.

 * 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,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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

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package sun.security.util;

import java.security.Key;

import java.security.PrivilegedAction;

import java.security.AccessController;

import java.security.interfaces.ECKey;

import java.security.interfaces.RSAKey;

import java.security.interfaces.DSAKey;

import javax.crypto.SecretKey;

import javax.crypto.interfaces.DHKey;

/**

 * A utility class to get key length

 */

public final class KeyLength {

    /**

     * Returns the key size of the given key object in bits.

     *

     * @param key the key object, cannot be null

     * @return the key size of the given key object in bits, or -1 if the

     *       key size is not accessible

     */

    final public static int getKeySize(Key key) {

        int size = -1;

        if (key instanceof Length) {

            try {

                Length ruler = (Length)key;

                size = ruler.length();

            } catch (UnsupportedOperationException usoe) {

                // ignore the exception

            }

            if (size >= 0) {

                return size;

            }

        }

        // try to parse the length from key specification

        if (key instanceof SecretKey) {

            SecretKey sk = (SecretKey)key;

            String format = sk.getFormat();

            if ("RAW".equals(format) && sk.getEncoded() != null) {

                size = (sk.getEncoded().length * 8);

            }   // Otherwise, it may be a unextractable key of PKCS#11, or

                // a key we are not able to handle.

        } else if (key instanceof RSAKey) {

            RSAKey pubk = (RSAKey)key;

            size = pubk.getModulus().bitLength();

        } else if (key instanceof ECKey) {

            ECKey pubk = (ECKey)key;

            size = pubk.getParams().getOrder().bitLength();

        } else if (key instanceof DSAKey) {

            DSAKey pubk = (DSAKey)key;

            size = pubk.getParams().getP().bitLength();

        } else if (key instanceof DHKey) {

            DHKey pubk = (DHKey)key;

            size = pubk.getParams().getP().bitLength();

        }   // Otherwise, it may be a unextractable key of PKCS#11, or

            // a key we are not able to handle.

        return size;

    }

}