Source for gnu.java.security.key.rsa.GnuRSAPublicKey

   1: /* GnuRSAPublicKey.java --
   2:    Copyright 2001, 2002, 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.java.security.key.rsa;
  40: 
  41: import gnu.java.lang.CPStringBuilder;
  42: 
  43: import gnu.java.security.Registry;
  44: import gnu.java.security.action.GetPropertyAction;
  45: import gnu.java.security.key.IKeyPairCodec;
  46: 
  47: import java.math.BigInteger;
  48: import java.security.AccessController;
  49: import java.security.PublicKey;
  50: import java.security.interfaces.RSAPublicKey;
  51: 
  52: /**
  53:  * An object that encapsulates an RSA public key.
  54:  * <p>
  55:  * References:
  56:  * <ol>
  57:  * <li><a
  58:  * href="http://www.cosic.esat.kuleuven.ac.be/nessie/workshop/submissions/rsa-pss.zip">
  59:  * RSA-PSS Signature Scheme with Appendix, part B.</a><br>
  60:  * Primitive specification and supporting documentation.<br>
  61:  * Jakob Jonsson and Burt Kaliski.</li>
  62:  * </ol>
  63:  */
  64: public class GnuRSAPublicKey
  65:     extends GnuRSAKey
  66:     implements PublicKey, RSAPublicKey
  67: {
  68:   /** String representation of this key. Cached for speed. */
  69:   private transient String str;
  70: 
  71:   /**
  72:    * Conveience constructor. Calls the constructor with 3 arguments passing
  73:    * {@link Registry#RAW_ENCODING_ID} as the identifier of the preferred
  74:    * encoding format.
  75:    *
  76:    * @param n the modulus.
  77:    * @param e the public exponent.
  78:    */
  79:   public GnuRSAPublicKey(final BigInteger n, final BigInteger e)
  80:   {
  81:     this(Registry.RAW_ENCODING_ID, n, e);
  82:   }
  83: 
  84:   /**
  85:    * Constructs a new instance of <code>GnuRSAPublicKey</code> given the
  86:    * designated arguments.
  87:    *
  88:    * @param preferredFormat the identifier of the preferred encoding format to
  89:    *          use when externalizing this key.
  90:    * @param n the modulus.
  91:    * @param e the public exponent.
  92:    */
  93:   public GnuRSAPublicKey(int preferredFormat, BigInteger n, BigInteger e)
  94:   {
  95:     super(preferredFormat == Registry.ASN1_ENCODING_ID ? Registry.X509_ENCODING_ID
  96:                                                        : preferredFormat,
  97:           n, e);
  98:   }
  99: 
 100:   /**
 101:    * A class method that takes the output of the <code>encodePublicKey()</code>
 102:    * method of an RSA keypair codec object (an instance implementing
 103:    * {@link IKeyPairCodec} for RSA keys, and re-constructs an instance of this
 104:    * object.
 105:    *
 106:    * @param k the contents of a previously encoded instance of this object.
 107:    * @throws ArrayIndexOutOfBoundsException if there is not enough bytes, in
 108:    *           <code>k</code>, to represent a valid encoding of an instance
 109:    *           of this object.
 110:    * @throws IllegalArgumentException if the byte sequence does not represent a
 111:    *           valid encoding of an instance of this object.
 112:    */
 113:   public static GnuRSAPublicKey valueOf(final byte[] k)
 114:   {
 115:     // try RAW codec
 116:     if (k[0] == Registry.MAGIC_RAW_RSA_PUBLIC_KEY[0])
 117:       try
 118:         {
 119:           return (GnuRSAPublicKey) new RSAKeyPairRawCodec().decodePublicKey(k);
 120:         }
 121:       catch (IllegalArgumentException ignored)
 122:         {
 123:         }
 124:     // try X.509 codec
 125:     return (GnuRSAPublicKey) new RSAKeyPairX509Codec().decodePublicKey(k);
 126:   }
 127: 
 128:   /**
 129:    * Returns the encoded form of this public key according to the designated
 130:    * format.
 131:    *
 132:    * @param format the desired format identifier of the resulting encoding.
 133:    * @return the byte sequence encoding this key according to the designated
 134:    *         format.
 135:    * @throws IllegalArgumentException if the format is not supported.
 136:    * @see RSAKeyPairRawCodec
 137:    */
 138:   public byte[] getEncoded(final int format)
 139:   {
 140:     final byte[] result;
 141:     switch (format)
 142:       {
 143:       case IKeyPairCodec.RAW_FORMAT:
 144:         result = new RSAKeyPairRawCodec().encodePublicKey(this);
 145:         break;
 146:       case IKeyPairCodec.X509_FORMAT:
 147:         result = new RSAKeyPairX509Codec().encodePublicKey(this);
 148:         break;
 149:       default:
 150:         throw new IllegalArgumentException("Unsupported encoding format: "
 151:                                            + format);
 152:       }
 153:     return result;
 154:   }
 155: 
 156:   /**
 157:    * Returns <code>true</code> if the designated object is an instance of this
 158:    * class and has the same RSA parameter values as this one.
 159:    *
 160:    * @param obj the other non-null RSA key to compare to.
 161:    * @return <code>true</code> if the designated object is of the same type
 162:    *         and value as this one.
 163:    */
 164:   public boolean equals(final Object obj)
 165:   {
 166:     if (obj == null)
 167:       return false;
 168: 
 169:     if (! (obj instanceof RSAPublicKey))
 170:       return false;
 171: 
 172:     final RSAPublicKey that = (RSAPublicKey) obj;
 173:     return super.equals(that)
 174:            && getPublicExponent().equals(that.getPublicExponent());
 175:   }
 176: 
 177:   public String toString()
 178:   {
 179:     if (str == null)
 180:       {
 181:         String ls = (String) AccessController.doPrivileged
 182:             (new GetPropertyAction("line.separator"));
 183:         str = new CPStringBuilder(this.getClass().getName()).append("(")
 184:             .append(super.toString()).append(",").append(ls)
 185:             .append(")")
 186:             .toString();
 187:       }
 188:     return str;
 189:   }
 190: }