1 /*

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

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

     4  *

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

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

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

    20  *

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

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.security.util;

    27 

    28 import java.security.Key;

    29 import java.security.PrivilegedAction;

    30 import java.security.AccessController;

    31 import java.security.interfaces.ECKey;

    32 import java.security.interfaces.RSAKey;

    33 import java.security.interfaces.DSAKey;

    34 import javax.crypto.SecretKey;

    35 import javax.crypto.interfaces.DHKey;

    36 

    37 /**

    38  * A utility class to get key length

    39  */

    40 public final class KeyLength {

    41 

    42     /**

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

    44      *

    45      * @param key the key object, cannot be null

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

    47      *       key size is not accessible

    48      */

    49     final public static int getKeySize(Key key) {

    50         int size = -1;

    51 

    52         if (key instanceof Length) {

    53             try {

    54                 Length ruler = (Length)key;

    55                 size = ruler.length();

    56             } catch (UnsupportedOperationException usoe) {

    57                 // ignore the exception

    58             }

    59 

    60             if (size >= 0) {

    61                 return size;

    62             }

    63         }

    64 

    65         // try to parse the length from key specification

    66         if (key instanceof SecretKey) {

    67             SecretKey sk = (SecretKey)key;

    68             String format = sk.getFormat();

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

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

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

    72                 // a key we are not able to handle.

    73         } else if (key instanceof RSAKey) {

    74             RSAKey pubk = (RSAKey)key;

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

    76         } else if (key instanceof ECKey) {

    77             ECKey pubk = (ECKey)key;

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

    79         } else if (key instanceof DSAKey) {

    80             DSAKey pubk = (DSAKey)key;

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

    82         } else if (key instanceof DHKey) {

    83             DHKey pubk = (DHKey)key;

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

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

    86             // a key we are not able to handle.

    87 

    88         return size;

    89     }

    90 }

    91