libjava/classpath/gnu/java/security/sig/ISignature.java

   1 /* ISignature.java --
   2    Copyright (C) 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.sig;
  40
  41 import java.util.Map;
  42
  43 /**
  44  * <p>The visible methods of every signature-with-appendix scheme.</p>
  45  *
  46  * <p>The Handbook of Applied Cryptography (HAC), by A. Menezes &amp; al. states:
  47  * "Digital signature schemes which require the message as input to the
  48  * verification algorithm are called <i>digital signature schemes with
  49  * appendix</i>. ... They rely on cryptographic hash functions rather than
  50  * customised redundancy functions, and are less prone to existential forgery
  51  * attacks."</p>
  52  *
  53  * <p>References:</p>
  54  * <ol>
  55  *    <li><a href="http://www.cacr.math.uwaterloo.ca/hac/">Handbook of Applied
  56  *    Cryptography</a>, Alfred J. Menezes, Paul C. van Oorschot and Scott A.
  57  *    Vanstone. Section 11.2.2 Digital signature schemes with appendix.</li>
  58  * </ol>
  59  */
  60 public interface ISignature extends Cloneable
  61 {
  62
  63   // Constants
  64   // -------------------------------------------------------------------------
  65
  66   /** Property name of the verifier's public key. */
  67   public static final String VERIFIER_KEY = "gnu.crypto.sig.public.key";
  68
  69   /** Property name of the signer's private key. */
  70   public static final String SIGNER_KEY = "gnu.crypto.sig.private.key";
  71
  72   /**
  73    * Property name of an optional {@link java.security.SecureRandom},
  74    * {@link java.util.Random}, or {@link gnu.crypto.prng.IRandom} instance to
  75    * use. The default is to use a classloader singleton from
  76    * {@link gnu.crypto.util.PRNG}.
  77    */
  78   public static final String SOURCE_OF_RANDOMNESS = "gnu.crypto.sig.prng";
  79
  80   // Methods
  81   // -------------------------------------------------------------------------
  82
  83   /**
  84    * <p>Returns the canonical name of this signature scheme.</p>
  85    *
  86    * @return the canonical name of this instance.
  87    */
  88   String name();
  89
  90   /**
  91    * <p>Initialises this instance for signature verification.</p>
  92    *
  93    * @param attributes the attributes to use for setting up this instance.
  94    * @throws IllegalArgumentException if the designated public key is not
  95    * appropriate for this signature scheme.
  96    * @see #SOURCE_OF_RANDOMNESS
  97    * @see #VERIFIER_KEY
  98    */
  99   void setupVerify(Map attributes) throws IllegalArgumentException;
 100
 101   /**
 102    * <p>Initialises this instance for signature generation.</p>
 103    *
 104    * @param attributes the attributes to use for setting up this instance.
 105    * @throws IllegalArgumentException if the designated private key is not
 106    * appropriate for this signature scheme.
 107    * @see #SOURCE_OF_RANDOMNESS
 108    * @see #SIGNER_KEY
 109    */
 110   void setupSign(Map attributes) throws IllegalArgumentException;
 111
 112   /**
 113    * <p>Digests one byte of a message for signing or verification purposes.</p>
 114    *
 115    * @param b the message byte to digest.
 116    * @throws IllegalStateException if this instance was not setup for
 117    * signature generation/verification.
 118    */
 119   void update(byte b) throws IllegalStateException;
 120
 121   /**
 122    * <p>Digests a sequence of bytes from a message for signing or verification
 123    * purposes.</p>
 124    *
 125    * @param buffer the byte sequence to consider.
 126    * @param offset the byte poisition in <code>buffer</code> of the first byte
 127    * to consider.
 128    * @param length the number of bytes in <code>buffer</code> starting from the
 129    * byte at index <code>offset</code> to digest.
 130    * @throws IllegalStateException if this instance was not setup for
 131    * signature generation/verification.
 132    */
 133   void update(byte[] buffer, int offset, int length)
 134       throws IllegalStateException;
 135
 136   /**
 137    * <p>Terminates a signature generation phase by digesting and processing the
 138    * context of the underlying message digest algorithm instance.</p>
 139    *
 140    * @return a {@link Object} representing the native output of the signature
 141    * scheme implementation.
 142    * @throws IllegalStateException if this instance was not setup for
 143    * signature generation.
 144    */
 145   Object sign() throws IllegalStateException;
 146
 147   /**
 148    * <p>Terminates a signature verification phase by digesting and processing
 149    * the context of the underlying message digest algorithm instance.</p>
 150    *
 151    * @param signature a native signature object previously generated by an
 152    * invocation of the <code>sign()</code> method.
 153    * @return <code>true</code> iff the outpout of the verification phase
 154    * confirms that the designated signature object has been generated using the
 155    * corresponding public key of the recepient.
 156    * @throws IllegalStateException if this instance was not setup for
 157    * signature verification.
 158    */
 159   boolean verify(Object signature) throws IllegalStateException;
 160
 161   /**
 162    * <p>Returns a clone copy of this instance.</p>
 163    *
 164    * @return a clone copy of this instance.
 165    */
 166   Object clone();
 167 }