Source for gnu.javax.crypto.key.dh.GnuDHPrivateKey

   1: /* GnuDHPrivateKey.java --
   2:    Copyright (C) 2003, 2006 Free Software Foundation, Inc.
   3: 
   4: This file is a 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 of the License, or (at
   9: your option) 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; if not, write to the Free Software
  18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19: 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.javax.crypto.key.dh;
  40: 
  41: import gnu.java.security.Configuration;
  42: import gnu.java.security.Registry;
  43: import gnu.java.security.action.GetPropertyAction;
  44: import gnu.java.security.key.IKeyPairCodec;
  45: 
  46: import java.math.BigInteger;
  47: import java.security.AccessController;
  48: 
  49: import javax.crypto.interfaces.DHPrivateKey;
  50: 
  51: /**
  52:  * An implementation of the Diffie-Hellman private key.
  53:  * <p>
  54:  * Reference:
  55:  * <ol>
  56:  * <li><a href="http://www.ietf.org/rfc/rfc2631.txt">Diffie-Hellman Key
  57:  * Agreement Method</a><br>
  58:  * Eric Rescorla.</li>
  59:  * </ol>
  60:  */
  61: public class GnuDHPrivateKey
  62:     extends GnuDHKey
  63:     implements DHPrivateKey
  64: {
  65:   /** The private exponent. */
  66:   private final BigInteger x;
  67:   /** String representation of this key. Cached for speed. */
  68:   private transient String str;
  69: 
  70:   /**
  71:    * Convenience constructor. Calls the constructor with five arguments passing
  72:    * {@link Registry#RAW_ENCODING_ID} as the value of its first argument.
  73:    *
  74:    * @param q a prime divisor of p-1.
  75:    * @param p the public prime.
  76:    * @param g the generator of the group.
  77:    * @param x the private value x.
  78:    */
  79:   public GnuDHPrivateKey(BigInteger q, BigInteger p, BigInteger g, BigInteger x)
  80:   {
  81:     this(Registry.RAW_ENCODING_ID, q, p, g, x);
  82:   }
  83: 
  84:   /**
  85:    * Constructs a new instance of <code>GnuDHPrivateKey</code> given the
  86:    * designated parameters.
  87:    *
  88:    * @param preferredFormat the identifier of the encoding format to use by
  89:    *          default when externalizing the key.
  90:    * @param q a prime divisor of p-1.
  91:    * @param p the public prime.
  92:    * @param g the generator of the group.
  93:    * @param x the private value x.
  94:    */
  95:   public GnuDHPrivateKey(int preferredFormat, BigInteger q, BigInteger p,
  96:                          BigInteger g, BigInteger x)
  97:   {
  98:     super(preferredFormat == Registry.ASN1_ENCODING_ID ? Registry.PKCS8_ENCODING_ID
  99:                                                        : preferredFormat,
 100:           q, p, g);
 101:     this.x = x;
 102:   }
 103: 
 104:   /**
 105:    * A class method that takes the output of the <code>encodePrivateKey()</code>
 106:    * method of a DH keypair codec object (an instance implementing
 107:    * {@link IKeyPairCodec} for DH keys, and re-constructs an instance of this
 108:    * object.
 109:    *
 110:    * @param k the contents of a previously encoded instance of this object.
 111:    * @exception ArrayIndexOutOfBoundsException if there is not enough bytes, in
 112:    *              <code>k</code>, to represent a valid encoding of an
 113:    *              instance of this object.
 114:    * @exception IllegalArgumentException if the byte sequence does not represent
 115:    *              a valid encoding of an instance of this object.
 116:    */
 117:   public static GnuDHPrivateKey valueOf(byte[] k)
 118:   {
 119:     // try RAW codec
 120:     if (k[0] == Registry.MAGIC_RAW_DH_PRIVATE_KEY[0])
 121:       try
 122:         {
 123:           return (GnuDHPrivateKey) new DHKeyPairRawCodec().decodePrivateKey(k);
 124:         }
 125:       catch (IllegalArgumentException ignored)
 126:         {
 127:         }
 128:     // try PKCS#8 codec
 129:     return (GnuDHPrivateKey) new DHKeyPairPKCS8Codec().decodePrivateKey(k);
 130:   }
 131: 
 132:   public BigInteger getX()
 133:   {
 134:     return x;
 135:   }
 136: 
 137:   /**
 138:    * Returns the encoded form of this private key according to the designated
 139:    * format.
 140:    *
 141:    * @param format the desired format identifier of the resulting encoding.
 142:    * @return the byte sequence encoding this key according to the designated
 143:    *         format.
 144:    * @exception IllegalArgumentException if the format is not supported.
 145:    * @see DHKeyPairRawCodec
 146:    */
 147:   public byte[] getEncoded(int format)
 148:   {
 149:     byte[] result;
 150:     switch (format)
 151:       {
 152:       case IKeyPairCodec.RAW_FORMAT:
 153:         result = new DHKeyPairRawCodec().encodePrivateKey(this);
 154:         break;
 155:       case IKeyPairCodec.PKCS8_FORMAT:
 156:         result = new DHKeyPairPKCS8Codec().encodePrivateKey(this);
 157:         break;
 158:       default:
 159:         throw new IllegalArgumentException("Unsupported encoding format: "
 160:                                            + format);
 161:       }
 162:     return result;
 163:   }
 164: 
 165:   /**
 166:    * Returns <code>true</code> if the designated object is an instance of
 167:    * {@link DHPrivateKey} and has the same parameter values as this one.
 168:    *
 169:    * @param obj the other non-null DH key to compare to.
 170:    * @return <code>true</code> if the designated object is of the same type
 171:    *         and value as this one.
 172:    */
 173:   public boolean equals(Object obj)
 174:   {
 175:     if (obj == null)
 176:       return false;
 177: 
 178:     if (! (obj instanceof DHPrivateKey))
 179:       return false;
 180: 
 181:     DHPrivateKey that = (DHPrivateKey) obj;
 182:     return super.equals(that) && x.equals(that.getX());
 183:   }
 184: 
 185:   public String toString()
 186:   {
 187:     if (str == null)
 188:       {
 189:         String ls = (String) AccessController.doPrivileged
 190:             (new GetPropertyAction("line.separator"));
 191:         str = new StringBuilder(this.getClass().getName()).append("(")
 192:             .append(super.toString()).append(",").append(ls)
 193:             .append("x=0x").append(Configuration.DEBUG ? x.toString(16)
 194:                                                        : "**...*").append(ls)
 195:             .append(")")
 196:             .toString();
 197:       }
 198:     return str;
 199:   }
 200: }