Source for javax.crypto.KeyAgreementSpi

   1: /* KeyAgreementSpi.java -- The key agreement service provider interface.
   2:    Copyright (C) 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 javax.crypto;
  40: 
  41: import java.security.InvalidAlgorithmParameterException;
  42: import java.security.InvalidKeyException;
  43: import java.security.Key;
  44: import java.security.NoSuchAlgorithmException;
  45: import java.security.SecureRandom;
  46: import java.security.spec.AlgorithmParameterSpec;
  47: 
  48: /**
  49:  * This is the <i>Service Provider Interface</i> (<b>SPI</b>) for the
  50:  * {@link javax.crypto.KeyAgreement} class.
  51:  *
  52:  * <p>Providers wishing to implement a key agreement algorithm must
  53:  * subclass this and provide an appropriate implementation for all the
  54:  * abstract methods below, and provide an appropriate entry in the
  55:  * master {@link java.security.Provider} class (the service name for key
  56:  * agreement algorithms is <code>"KeyAgreement"</code>).
  57:  *
  58:  * @author Casey Marshall (csm@gnu.org)
  59:  * @since 1.4
  60:  * @see KeyAgreement
  61:  * @see SecretKey
  62:  */
  63: public abstract class KeyAgreementSpi
  64: {
  65: 
  66:   // Constructor.
  67:   // ------------------------------------------------------------------------
  68: 
  69:   /**
  70:    * Create a new KeyAgreementSpi instance.
  71:    */
  72:   public KeyAgreementSpi()
  73:   {
  74:   }
  75: 
  76:   // Abstract instance methods.
  77:   // ------------------------------------------------------------------------
  78: 
  79:   /**
  80:    * Do a phase in the key agreement.
  81:    *
  82:    * @param key The key to use for this phase.
  83:    * @param lastPhase <code>true</code> if this call should be the last
  84:    *        phase.
  85:    * @return The intermediate result, or <code>null</code> if there is
  86:    *         no intermediate result.
  87:    * @throws java.lang.IllegalStateException If this instance has not
  88:    *         been initialized.
  89:    * @throws java.security.InvalidKeyException If the supplied key is
  90:    *         not appropriate.
  91:    */
  92:   protected abstract Key engineDoPhase(Key key, boolean lastPhase)
  93:     throws IllegalStateException, InvalidKeyException;
  94: 
  95:   /**
  96:    * Generate the shared secret in a new byte array.
  97:    *
  98:    * @return The shared secret in a new byte array.
  99:    * @throws java.lang.IllegalStateException If this key agreement is
 100:    *         not ready to generate the secret.
 101:    */
 102:   protected abstract byte[] engineGenerateSecret()
 103:     throws IllegalStateException;
 104: 
 105:   /**
 106:    * Generate the shared secret, storing it into the specified array.
 107:    *
 108:    * @param sharedSecret The byte array in which to store the secret.
 109:    * @param offset       The offset into the byte array to start.
 110:    * @return The size of the shared secret.
 111:    * @throws java.lang.IllegalStateException If this key agreement is
 112:    *         not ready to generate the secret.
 113:    * @throws javax.crypto.ShortBufferException If there is not enough
 114:    *         space in the supplied array for the shared secret.
 115:    */
 116:   protected abstract int engineGenerateSecret(byte[] sharedSecret, int offset)
 117:     throws IllegalStateException, ShortBufferException;
 118: 
 119:   /**
 120:    * Generate the shared secret and return it as a {@link SecretKey}.
 121:    *
 122:    * @param algorithm The algorithm with which to generate the secret key.
 123:    * @return The shared secret as a secret key.
 124:    * @throws java.lang.IllegalStateException If this key agreement is
 125:    *         not ready to generate the secret.
 126:    * @throws java.security.InvalidKeyException If the shared secret
 127:    *         cannot be made into a {@link SecretKey}.
 128:    * @throws java.security.NoSuchAlgorithmException If
 129:    *         <code>algorithm</code> cannot be found.
 130:    */
 131:   protected abstract SecretKey engineGenerateSecret(String algorithm)
 132:     throws IllegalStateException, InvalidKeyException, NoSuchAlgorithmException;
 133: 
 134:   /**
 135:    * Initialize this key agreement with a key, parameters, and source of
 136:    * randomness.
 137:    *
 138:    * @param key    The key to initialize with, usually a private key.
 139:    * @param params The parameters to initialize with.
 140:    * @param random The source of randomness to use.
 141:    * @throws java.security.InvalidAlgorithmParameterException If the
 142:    *         supplied parameters are inappropriate.
 143:    * @throws java.security.InvalidKeyException If the supplied key is
 144:    *         inappropriate.
 145:    */
 146:   protected abstract void engineInit(Key key, AlgorithmParameterSpec params,
 147:                                      SecureRandom random)
 148:     throws InvalidAlgorithmParameterException, InvalidKeyException;
 149: 
 150:   /**
 151:    * Initialize this key agreement with a key and source of randomness.
 152:    *
 153:    * @param key    The key to initialize with, usually a private key.
 154:    * @param random The source of randomness to use.
 155:    * @throws java.security.InvalidKeyException If the supplied key is
 156:    *         inappropriate.
 157:    */
 158:   protected abstract void engineInit(Key key, SecureRandom random)
 159:     throws InvalidKeyException;
 160: }