libjava/gnu/java/security/provider/GnuDSAPublicKey.java

   1 /* GnuDSAPublicKey.java --- Gnu DSA Public Key
   2    Copyright (C) 1999,2003,2004 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package gnu.java.security.provider;
  40
  41 import gnu.java.security.OID;
  42 import gnu.java.security.der.BitString;
  43 import gnu.java.security.der.DER;
  44 import gnu.java.security.der.DERValue;
  45 import gnu.java.security.der.DERWriter;
  46
  47 import java.io.ByteArrayOutputStream;
  48 import java.io.IOException;
  49
  50 import java.math.BigInteger;
  51
  52 import java.security.interfaces.DSAPublicKey;
  53 import java.security.interfaces.DSAParams;
  54 import java.security.spec.DSAParameterSpec;
  55
  56 import java.util.ArrayList;
  57
  58 public class GnuDSAPublicKey implements DSAPublicKey
  59 {
  60   private byte[] encodedKey;
  61   BigInteger y;
  62   BigInteger p;
  63   BigInteger q;
  64   BigInteger g;
  65
  66   public GnuDSAPublicKey(BigInteger y, BigInteger p, BigInteger q, BigInteger g )
  67   {
  68     this.y = y;
  69     this.p = p;
  70     this.q = q;
  71     this.g = g;
  72   }
  73
  74   public String getAlgorithm()
  75   {
  76     return "DSA";
  77   }
  78
  79   public String getFormat()
  80   {
  81     return "X.509";
  82   }
  83
  84   /**
  85    * The encoded form of DSA public keys is:
  86    *
  87    * <blockquote><pre>
  88    * SubjectPublicKeyInfo ::= SEQUENCE {
  89    *   algorithm AlgorithmIdentifier,
  90    *   subjectPublicKey BIT STRING }
  91    * </pre></blockquote>
  92    */
  93   public byte[] getEncoded()
  94   {
  95     if (encodedKey != null)
  96       return (byte[]) encodedKey.clone();
  97     try
  98       {
  99         ByteArrayOutputStream out = new ByteArrayOutputStream();
 100         ArrayList spki = new ArrayList(2);
 101         ArrayList alg = new ArrayList(2);
 102         alg.add(new DERValue(DER.OBJECT_IDENTIFIER,
 103                 new OID("1.2.840.113549.1.1.1")));
 104         ArrayList params = new ArrayList(3);
 105         params.add(new DERValue(DER.INTEGER, p));
 106         params.add(new DERValue(DER.INTEGER, q));
 107         params.add(new DERValue(DER.INTEGER, g));
 108         alg.add(new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, params));
 109         spki.add(new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, alg));
 110         spki.add(new DERValue(DER.BIT_STRING, new BitString(y.toByteArray())));
 111         DERWriter.write(out, new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, spki));
 112         return (byte[]) (encodedKey = out.toByteArray()).clone();
 113       }
 114     catch (IOException ioe)
 115       {
 116         return null;
 117       }
 118   }
 119
 120   public DSAParams getParams()
 121   {
 122     if (p == null || q == null || g == null)
 123       return null;
 124     return (DSAParams)(new DSAParameterSpec(p,q,g));
 125   }
 126
 127   public BigInteger getY()
 128   {
 129     return y;
 130   }
 131
 132   public String toString()
 133   {
 134     return
 135       "GnuDSAPublicKey: y=" + (y != null ? y.toString(16) : "(null)") +
 136       " p=" + (p != null ? p.toString(16) : "(null)") +
 137       " q=" + (q != null ? q.toString(16) : "(null)") +
 138       " g=" + (g != null ? g.toString(16) : "(null)");
 139   }
 140 }