1 /*

     2  * Copyright (c) 1996, 2013, 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.provider;

    27 

    28 import java.util.*;

    29 import java.io.*;

    30 import java.math.BigInteger;

    31 import java.security.InvalidKeyException;

    32 import java.security.ProviderException;

    33 import java.security.AlgorithmParameters;

    34 import java.security.spec.DSAParameterSpec;

    35 import java.security.spec.InvalidParameterSpecException;

    36 import java.security.interfaces.DSAParams;

    37 

    38 import sun.security.x509.X509Key;

    39 import sun.security.x509.AlgIdDSA;

    40 import sun.security.util.BitArray;

    41 import sun.security.util.Debug;

    42 import sun.security.util.DerValue;

    43 import sun.security.util.DerInputStream;

    44 import sun.security.util.DerOutputStream;

    45 

    46 /**

    47  * An X.509 public key for the Digital Signature Algorithm.

    48  *

    49  * @author Benjamin Renaud

    50  *

    51  *

    52  * @see DSAPrivateKey

    53  * @see AlgIdDSA

    54  * @see DSA

    55  */

    56 

    57 public class DSAPublicKey extends X509Key

    58 implements java.security.interfaces.DSAPublicKey, Serializable {

    59 

    60     /** use serialVersionUID from JDK 1.1. for interoperability */

    61     private static final long serialVersionUID = -2994193307391104133L;

    62 

    63     /* the public key */

    64     private BigInteger y;

    65 

    66     /*

    67      * Keep this constructor for backwards compatibility with JDK1.1.

    68      */

    69     public DSAPublicKey() {

    70     }

    71 

    72     /**

    73      * Make a DSA public key out of a public key and three parameters.

    74      * The p, q, and g parameters may be null, but if so, parameters will need

    75      * to be supplied from some other source before this key can be used in

    76      * cryptographic operations.  PKIX RFC2459bis explicitly allows DSA public

    77      * keys without parameters, where the parameters are provided in the

    78      * issuer's DSA public key.

    79      *

    80      * @param y the actual key bits

    81      * @param p DSA parameter p, may be null if all of p, q, and g are null.

    82      * @param q DSA parameter q, may be null if all of p, q, and g are null.

    83      * @param g DSA parameter g, may be null if all of p, q, and g are null.

    84      */

    85     public DSAPublicKey(BigInteger y, BigInteger p, BigInteger q,

    86                         BigInteger g)

    87     throws InvalidKeyException {

    88         this.y = y;

    89         algid = new AlgIdDSA(p, q, g);

    90 

    91         try {

    92             byte[] keyArray = new DerValue(DerValue.tag_Integer,

    93                                y.toByteArray()).toByteArray();

    94             setKey(new BitArray(keyArray.length*8, keyArray));

    95             encode();

    96         } catch (IOException e) {

    97             throw new InvalidKeyException("could not DER encode y: " +

    98                                           e.getMessage());

    99         }

   100     }

   101 

   102     /**

   103      * Make a DSA public key from its DER encoding (X.509).

   104      */

   105     public DSAPublicKey(byte[] encoded) throws InvalidKeyException {

   106         decode(encoded);

   107     }

   108 

   109     /**

   110      * Returns the DSA parameters associated with this key, or null if the

   111      * parameters could not be parsed.

   112      */

   113     public DSAParams getParams() {

   114         try {

   115             if (algid instanceof DSAParams) {

   116                 return (DSAParams)algid;

   117             } else {

   118                 DSAParameterSpec paramSpec;

   119                 AlgorithmParameters algParams = algid.getParameters();

   120                 if (algParams == null) {

   121                     return null;

   122                 }

   123                 paramSpec = algParams.getParameterSpec(DSAParameterSpec.class);

   124                 return (DSAParams)paramSpec;

   125             }

   126         } catch (InvalidParameterSpecException e) {

   127             return null;

   128         }

   129     }

   130 

   131     /**

   132      * Get the raw public value, y, without the parameters.

   133      *

   134      * @see getParameters

   135      */

   136     public BigInteger getY() {

   137         return y;

   138     }

   139 

   140     public String toString() {

   141         return "Sun DSA Public Key\n    Parameters:" + algid

   142             + "\n  y:\n" + Debug.toHexString(y) + "\n";

   143     }

   144 

   145     protected void parseKeyBits() throws InvalidKeyException {

   146         try {

   147             DerInputStream in = new DerInputStream(getKey().toByteArray());

   148             y = in.getBigInteger();

   149         } catch (IOException e) {

   150             throw new InvalidKeyException("Invalid key: y value\n" +

   151                                           e.getMessage());

   152         }

   153     }

   154 }