libjava/gnu/java/security/provider/DSAParameters.java

   1 /* DSAParameters.java --- DSA Parameters Implementation
   2    Copyright (C) 1999,2003 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 java.io.ByteArrayInputStream;
  42 import java.io.ByteArrayOutputStream;
  43 import java.io.IOException;
  44
  45 import java.math.BigInteger;
  46
  47 import java.security.AlgorithmParametersSpi;
  48 import java.security.InvalidAlgorithmParameterException;
  49 import java.security.spec.AlgorithmParameterSpec;
  50 import java.security.spec.DSAParameterSpec;
  51 import java.security.spec.InvalidParameterSpecException;
  52
  53 import java.util.ArrayList;
  54 import java.util.List;
  55 import java.util.Random;
  56
  57 import gnu.java.io.ASN1ParsingException;
  58 import gnu.java.security.der.DER;
  59 import gnu.java.security.der.DEREncodingException;
  60 import gnu.java.security.der.DERReader;
  61 import gnu.java.security.der.DERValue;
  62 import gnu.java.security.der.DERWriter;
  63
  64 import gnu.java.security.util.Prime;
  65
  66 /*
  67         ASN.1 Encoding for DSA from rfc2459
  68
  69         id-dsa ID ::= { iso(1) member-body(2) us(840) x9-57(10040)
  70                   x9cm(4) 1 }
  71
  72         Dss-Parms  ::=  SEQUENCE  {
  73             p             INTEGER,
  74             q             INTEGER,
  75             g             INTEGER  }
  76
  77 */
  78 public class DSAParameters extends AlgorithmParametersSpi
  79 {
  80 private BigInteger q; // the small prime
  81 private BigInteger p; // the big prime
  82 private BigInteger g;
  83
  84
  85 public void engineInit(AlgorithmParameterSpec paramSpec)
  86                             throws InvalidParameterSpecException
  87 {
  88         if( paramSpec instanceof DSAParameterSpec ) {
  89                 DSAParameterSpec dsaParamSpec = (DSAParameterSpec)paramSpec;
  90                 p = dsaParamSpec.getP();
  91                 q = dsaParamSpec.getQ();
  92                 g = dsaParamSpec.getG();
  93         }
  94         else
  95                 throw new InvalidParameterSpecException("Only accepts DSAParameterSpec");
  96 }
  97
  98 public void engineInit(byte[] params)
  99                             throws IOException
 100 {
 101         DERReader in = new DERReader(params);
 102         DERValue val = in.read();
 103         if (val.getValue() != DER.CONSTRUCTED_VALUE)
 104                 throw new ASN1ParsingException("badly formed parameters");
 105         try
 106                 {
 107                         p = (BigInteger) in.read().getValue();
 108                         q = (BigInteger) in.read().getValue();
 109                         g = (BigInteger) in.read().getValue();
 110                 }
 111         catch (Exception x)
 112                 {
 113                         throw new ASN1ParsingException("badly formed parameters");
 114                 }
 115 }
 116
 117 public void engineInit(byte[] params, String format)
 118                             throws IOException
 119 {
 120         if( !format.equals("ASN.1") )
 121                 throw new IOException("Invalid Format: Only accepts ASN.1");
 122         engineInit( params );
 123 }
 124
 125 public AlgorithmParameterSpec engineGetParameterSpec(Class paramSpec)
 126                           throws InvalidParameterSpecException
 127 {
 128         if( paramSpec.isAssignableFrom(DSAParameterSpec.class) )
 129                 return new DSAParameterSpec(p, q, g);
 130         else
 131                 throw new InvalidParameterSpecException("Only accepts DSAParameterSpec");
 132 }
 133
 134 public byte[] engineGetEncoded()
 135                                     throws IOException
 136 {
 137         ByteArrayOutputStream bout = new ByteArrayOutputStream();
 138         ArrayList seq = new ArrayList(3);
 139         seq.add(new DERValue(DER.INTEGER, p));
 140         seq.add(new DERValue(DER.INTEGER, q));
 141         seq.add(new DERValue(DER.INTEGER, g));
 142         DERWriter.write(bout, new DERValue(DER.CONSTRUCTED | DER.SEQUENCE, seq));
 143         return bout.toByteArray();
 144 }
 145
 146
 147 public byte[] engineGetEncoded(String format)
 148                                     throws IOException
 149 {
 150         if( !format.equals("ASN.1") )
 151                 throw new IOException("Invalid Format: Only accepts ASN.1");
 152         return engineGetEncoded();
 153 }
 154
 155 public String engineToString()
 156 {
 157         return ("q: " + q + " p: " + p + " g: " + g);
 158 }
 159
 160 }