libjava/classpath/gnu/java/security/jce/sig/DSSParametersGenerator.java

   1 /* DSSParametersGenerator.java -- JCE Adapter for a generator of DSS parameters
   2    Copyright (C) 2006 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.jce.sig;
  40
  41 import gnu.java.security.Registry;
  42 import gnu.java.security.key.dss.DSSKeyPairGenerator;
  43 import gnu.java.security.key.dss.FIPS186;
  44 import gnu.java.security.provider.Gnu;
  45
  46 import java.math.BigInteger;
  47 import java.security.AlgorithmParameterGeneratorSpi;
  48 import java.security.AlgorithmParameters;
  49 import java.security.InvalidAlgorithmParameterException;
  50 import java.security.InvalidParameterException;
  51 import java.security.NoSuchAlgorithmException;
  52 import java.security.Provider;
  53 import java.security.SecureRandom;
  54 import java.security.spec.AlgorithmParameterSpec;
  55 import java.security.spec.DSAParameterSpec;
  56 import java.security.spec.InvalidParameterSpecException;
  57
  58 /**
  59  * A JCE Adapter for a generator of DSS parameters.
  60  */
  61 public class DSSParametersGenerator
  62     extends AlgorithmParameterGeneratorSpi
  63 {
  64   private static final Provider GNU = new Gnu();
  65
  66   /** Size of the public modulus in bits. */
  67   private int modulusLength = -1;
  68
  69   /** User specified source of randomness. */
  70   private SecureRandom rnd;
  71
  72   /** Our concrete DSS parameters generator. */
  73   private FIPS186 fips;
  74
  75   // default 0-arguments constructor
  76
  77   protected void engineInit(int size, SecureRandom random)
  78   {
  79     if ((size % 64) != 0 || size < 512 || size > 1024)
  80       throw new InvalidParameterException("Modulus size/length (in bits) MUST "
  81                                           + "be a multiple of 64, greater than "
  82                                           + "or equal to 512, and less than or "
  83                                           + "equal to 1024");
  84     this.modulusLength = size;
  85     this.rnd = random;
  86   }
  87
  88   protected void engineInit(AlgorithmParameterSpec spec, SecureRandom random)
  89       throws InvalidAlgorithmParameterException
  90   {
  91     if (! (spec instanceof DSAParameterSpec))
  92       throw new InvalidAlgorithmParameterException("Wrong AlgorithmParameterSpec type: "
  93                                                    + spec.getClass().getName());
  94     DSAParameterSpec dsaSpec = (DSAParameterSpec) spec;
  95     BigInteger p = dsaSpec.getP();
  96     int size = p.bitLength();
  97     this.engineInit(size, random);
  98   }
  99
 100   protected AlgorithmParameters engineGenerateParameters()
 101   {
 102     if (modulusLength < 1)
 103       modulusLength = DSSKeyPairGenerator.DEFAULT_MODULUS_LENGTH;
 104
 105     fips = new FIPS186(modulusLength, rnd);
 106     BigInteger[] params = fips.generateParameters();
 107     BigInteger p = params[3];
 108     BigInteger q = params[2];
 109     BigInteger g = params[5];
 110     DSAParameterSpec spec = new DSAParameterSpec(p, q, g);
 111     AlgorithmParameters result = null;
 112     try
 113       {
 114         result = AlgorithmParameters.getInstance(Registry.DSS_KPG, GNU);
 115         result.init(spec);
 116       }
 117     catch (NoSuchAlgorithmException ignore)
 118       {
 119       }
 120     catch (InvalidParameterSpecException ignore)
 121       {
 122       }
 123     return result;
 124   }
 125 }