Source for gnu.java.security.provider.GnuDSAPublicKey

   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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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: import java.math.BigInteger;
  50: import java.security.interfaces.DSAParams;
  51: import java.security.interfaces.DSAPublicKey;
  52: import java.security.spec.DSAParameterSpec;
  53: import java.util.ArrayList;
  54: 
  55: public class GnuDSAPublicKey implements DSAPublicKey
  56: {
  57:   private byte[] encodedKey;
  58:   BigInteger y;
  59:   BigInteger p;
  60:   BigInteger q;
  61:   BigInteger g;
  62: 
  63:   public GnuDSAPublicKey(BigInteger y, BigInteger p, BigInteger q, BigInteger g )
  64:   {
  65:     this.y = y;
  66:     this.p = p;
  67:     this.q = q;
  68:     this.g = g;
  69:   }
  70: 
  71:   public String getAlgorithm()
  72:   {
  73:     return "DSA";
  74:   }
  75: 
  76:   public String getFormat()
  77:   {
  78:     return "X.509";
  79:   }
  80: 
  81:   /**
  82:    * The encoded form of DSA public keys is:
  83:    *
  84:    * <blockquote><pre>
  85:    * SubjectPublicKeyInfo ::= SEQUENCE {
  86:    *   algorithm AlgorithmIdentifier,
  87:    *   subjectPublicKey BIT STRING }
  88:    * </pre></blockquote>
  89:    */
  90:   public byte[] getEncoded()
  91:   {
  92:     if (encodedKey != null)
  93:       return (byte[]) encodedKey.clone();
  94:     try
  95:       {
  96:         ByteArrayOutputStream out = new ByteArrayOutputStream();
  97:         ArrayList spki = new ArrayList(2);
  98:         ArrayList alg = new ArrayList(2);
  99:         alg.add(new DERValue(DER.OBJECT_IDENTIFIER,
 100:                 new OID("1.2.840.113549.1.1.1")));
 101:         ArrayList params = new ArrayList(3);
 102:         params.add(new DERValue(DER.INTEGER, p));
 103:         params.add(new DERValue(DER.INTEGER, q));
 104:         params.add(new DERValue(DER.INTEGER, g));
 105:         alg.add(new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, params));
 106:         spki.add(new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, alg));
 107:         spki.add(new DERValue(DER.BIT_STRING, new BitString(y.toByteArray())));
 108:         DERWriter.write(out, new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, spki));
 109:         return (byte[]) (encodedKey = out.toByteArray()).clone();
 110:       }
 111:     catch (IOException ioe)
 112:       {
 113:         return null;
 114:       }
 115:   }
 116: 
 117:   public DSAParams getParams()
 118:   {
 119:     if (p == null || q == null || g == null)
 120:       return null;
 121:     return (DSAParams)(new DSAParameterSpec(p,q,g));
 122:   }
 123: 
 124:   public BigInteger getY()
 125:   {
 126:     return y;
 127:   }
 128: 
 129:   public String toString()
 130:   {
 131:     return
 132:       "GnuDSAPublicKey: y=" + (y != null ? y.toString(16) : "(null)") +
 133:       " p=" + (p != null ? p.toString(16) : "(null)") +
 134:       " q=" + (q != null ? q.toString(16) : "(null)") +
 135:       " g=" + (g != null ? g.toString(16) : "(null)");
 136:   }
 137: }