idea.java

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// $Id: IDEA.java,v 1.1.1.1 2002/08/27 12:32:09 grosbois Exp $
//
// $Log: IDEA.java,v $
// Revision 1.1.1.1  2002/08/27 12:32:09  grosbois
// Add cryptix 3.2
//
// Revision 1.4  2000/08/17 11:40:51  edwin
// java.* -> xjava.*
//
// Revision 1.3  1997/11/29 04:42:55  hopwood
// + Changes to engineUpdate method.
//
// + Fixed invertKey to do the right thing (i.e. nothing) when the native
//   library is being used.
// + Formatting changes.
//
// Revision 1.2  1997/11/20 19:31:39  hopwood
// + cryptix.util.* name changes.
//
// Revision 1.1.1.1  1997/11/03 22:36:56  hopwood
// + Imported to CVS (tagged as 'start').
//
// Revision 0.3.2.0  1997/08/21  David Hopwood
// + Removed all deprecated methods and fields. Cryptix 2.2 compatibility
//   is now handled by the separate cryptix.security.IDEA class.
// + Tightened some of the access specifiers (e.g. SPI methods were public,
//   and are now protected).
// + Ensured that this class is final, and added a comment that this is for
//   security reasons.
//   If it were not final, some VMs have a bug that would allow a subclass
//   that implements Cloneable to call Object's or Cipher's clone() method
//   using invokenonvirtual, which would duplicate the pointer to the native
//   state. Then calling finalize() on the original and using the clone (for
//   example) would result in freed memory being written to :-(.
// + Required native code version is 2.3.
//
// Revision 0.3.1.0  1997/07/14  David Hopwood
// + Blowfish, DES, IDEA, and Square 3.1.0 are now at the same API
//   level and in the same style.
// + Fixed security bug (out-of-bounds read) introduced in 3.0.1 -
//   same bug as for Blowfish 3.0.5.
// + Renamed outs variable in engineUpdate to temp, to avoid similarity
//   with out.
//
// Revision 0.3.0.1  1997/07/09  R. Naffah
// + Fully IJCE-compliant!
// + Tested OK with and without IDEA.DLL.
// + Re-wrote the JNI code to conform with modifs;
// + Changed method signatures to follow same style/params as the other
//   ciphers in the library;
// + Changed methods mul and inv to return shorts;
// + Now use one short[] as the session key;
// + Brought it to the same API level as Blowfish 3.0.5 and DES 3.0.2;
//
// Revision 0.3.0.0  1997/07/0?  David Hopwood
// + JCE, native linking, debugging, etc...
//
// Revision 0.2.5.2  1997/04/03  Systemics
// + Documentation.  Deprecated public variables and made methods private.
//
// Revision 0.2.5.1  1997/03/15  Jill Baker
// + Moved this file here from old namespace.
//
// Revision 0.2.5.0  1997/02/24  Systemics
// + Original version.
//
// $Endlog$
/*
 * Copyright (c) 1995-97 Systemics Ltd
 * on behalf of the Cryptix Development Team.  All rights reserved.
 */
 
package cryptix.provider.cipher;

import cryptix.util.core.Debug;
import cryptix.CryptixException;
import cryptix.util.core.ArrayUtil;
import cryptix.util.core.Hex;
import cryptix.provider.key.RawSecretKey;

import java.io.PrintWriter;
import xjava.security.Cipher;
import java.security.Key;
import java.security.InvalidKeyException;
import xjava.security.SymmetricCipher;

/**
 * IDEA is a block cipher with a key length of 16 bytes and a block length of
 * 8 bytes. It is highly popular, being the original cipher in PGP, and has
 * received a lot of cryptanalytic attention.
 * <p>
 * IDEA was written by Dr. X. Lai and Prof. J. Massey.
 * <p>
 * <b>References:</b>
 * <ol>
 *   <li> See the <a href="http://www.ascom.ch/Web/systec/security/idea.htm">IDEA page</a>
 *        for more details.
 *        <p>
 *   <li> The algorithm is subject to patent claims by
 *        <a href="http://www.ascom.ch/systec/">Ascom Systec Ltd</a>
 *        (applied for May 1991), and is
 *        <a href="http://www.ascom.ch/Web/systec/policy/normal/policy.html">licensable</a>.
 * </ol>
 * <p>
 *
 * <b>Copyright</b> &copy; 1995-1997
 * <a href="http://www.systemics.com/">Systemics Ltd</a> on behalf of the
 * <a href="http://www.systemics.com/docs/cryptix/">Cryptix Development Team</a>.
 * <br>All rights reserved.
 *
 * <p><b>$Revision: 1.1.1.1 $</b>
 * @author  Systemics Ltd
 * @author  David Hopwood
 * @author  Raif S. Naffah
 * @since   Cryptix 2.2.2
 */
public final class IDEA // must be final for security reasons
extends Cipher
implements SymmetricCipher
{

// Debugging methods and vars.
//...........................................................................

    private static final boolean DEBUG = Debug.GLOBAL_DEBUG;
    private static final boolean DEBUG_SLOW = Debug.GLOBAL_DEBUG_SLOW;
    private static final int debuglevel = DEBUG ? Debug.getLevel("IDEA") : 0;
    private static final PrintWriter err = DEBUG ? Debug.getOutput() : null;
    private static void debug(String s) { err.println("IDEA: " + s); }


// Native library linking methods and vars.
//...........................................................................

    private static NativeLink linkStatus = new NativeLink("IDEA", 2, 3);

    /**
     * Gets an object representing the native linking status of this class.
     */
    public static cryptix.util.core.LinkStatus getLinkStatus() { return linkStatus; }

    /**
     * The native reference to the current native key schedule
     * structure. Defaults to 0 but is set by native code after a
     * successful call to native_init().
     * <p>
     * IMPORTANT: Do not change the name of this variable without
     * duplicating the same in the native code.
     */
    private long native_cookie;

    /**
     * This object must be synchronized on while calling any native instance
     * method. It is null if the native code is not being used (e.g. the
     * library did not load successfully, or the user disabled its use in
     * the properties file).
     */
    private Object native_lock; // defaults to null

    private void link() {
        synchronized(linkStatus) {
            try {
                if (linkStatus.attemptLoad()) {
                    linkStatus.checkVersion(getLibMajorVersion(), getLibMinorVersion());
                    linkStatus.check(native_clinit());
                }
                if (linkStatus.useNative()) {
                    linkStatus.check(native_init());
                    native_lock = new Object();
                }
            } catch (UnsatisfiedLinkError e) {
                linkStatus.fail(e);
if (DEBUG && debuglevel > 2) debug(e.getMessage());
            }
if (DEBUG && debuglevel > 2) debug("Using native library? " + (native_lock != null));
        }
    }


// Native support API
//...........................................................................

    // The methods that get the library version.
    private native static int getLibMajorVersion();
    private native static int getLibMinorVersion();

    /**
     * Static initialization and self-test method for the native code.
     *
     * @return a string if an error occurred or null otherwise.
     */
    private native String native_clinit();

    /**
     * Initializes the native state for this cipher object and allocates
     * needed native storage for the internal key schedule. A reference
     * to the newly allocated space, if successful, is stored in the
     * instance variable <code>native_cookie</code>.
     *
     * @return a string if an error occurred or null otherwise.
     */
    private native String native_init();

    /**
     * This function expands the user key to an internal form.
     *
     * @param  cookie   a valid reference to the native key structure. This
     *                  value is set by the native library upon return from
     *                  native_init() (see link() method at the top).
     * @param  userKey  a byte array representing the user key
     * @return an error String, or null if there was no error
     */
    private native String native_ks(long cookie, byte[] userKey);

    /**
     * Encrypts/decrypts a data block.
     * <p>
     * FUTURE: possibly change this to be able to process more than one block,
     * to reduce native method call overhead.
     * <p>
     * SECURITY: the caller <strong>must</strong> ensure that:
     * <ul>
     *   <li> <code>in != null</code>
     *   <li> <code>out != null</code>
     *   <li> <code>inOffset >= 0</code>
     *   <li> <code>(long)inOffset + BLOCK_SIZE <= in.length</code>
     *   <li> <code>outOffset >= 0</code>
     *   <li> <code>(long)outOffset + BLOCK_SIZE <= out.length</code>
     * </ul>
     *
     * @param  cookie       a valid reference to the native key structure. This
     *                      value is set by the native library upon return from
     *                      native_init() (see link() method at the top).
     * @param  in           input array containing data to encrypt or decrypt
     *                      depending on the value of the encrypt boolean parameter.
     * @param  inOffset     index of where we should start reading from input.
     * @param  out          output array containing data decrypted or encrypted
     *                      depending on the value of the encrypt boolean parameter.
     * @param  outOffset    index of where we should start writing to output.
     * @param  encrypt      if true then encrypt, otherwise decrypt.
     * @return the number of bytes crypted (always BLOCK_SIZE) or 0 if an error
     *                      occurred.
     */
    private native int native_crypt(long cookie, byte[] in, int inOffset,
                                    byte[] out, int outOffset, boolean encrypt);

    /**
     * Finalizes the native state for this object.
     *
     * @return a string if an error occurred or null otherwise.
     */
    private native String native_finalize();


// IDEA constants and variables
//............................................................................

    private static final int
        ROUNDS = 8,
        BLOCK_SIZE = 8,
        KEY_LENGTH = 16;

    /**
     * The number of array elements in the expanded key schedule, i.e. both
     * encryption and decryption keys.
     * <p>
     * For IDEA this is <code>6 * ROUNDS + 4 = 52</code>.
     */
    private static final int INTERNAL_KEY_LENGTH = 52;

    /**
     * The key schedule.
     */
    private short[] ks = new short[INTERNAL_KEY_LENGTH];


// Constructor, finalizer, and clone()
//............................................................................

    /**
     * Constructs an IDEA cipher object, in the UNINITIALIZED state.
     * This calls the Cipher constructor with <i>implBuffering</i> false,
     * <i>implPadding</i> false and the provider set to "Cryptix".
     */
    public IDEA() {
        super(false, false, "Cryptix");
        link();
    }

    /**
     * Cleans up resources used by this instance, if necessary.
     */
    protected final void finalize() {
        if (native_lock != null) {
            synchronized(native_lock) {
                String error = native_finalize(); // may be called more than once
                if (error != null)
                    debug(error + " in native_finalize");
            }
        }
    }

    /**
     * Always throws a CloneNotSupportedException (cloning of ciphers is not
     * supported for security reasons).
     */
    public final Object clone() throws CloneNotSupportedException {
        throw new CloneNotSupportedException();
    }


// Implementation of JCE methods
//............................................................................
    
    /**
     * <b>SPI</b>: Returns the length of an input block, in bytes.
     *
     * @return the length in bytes of an input block for this cipher.
     */
    protected int engineBlockSize () { return BLOCK_SIZE; }

    /**
     * <b>SPI</b>: Initializes this cipher for encryption, using the
     * specified key.
     *
     * @param  key  the key to use for encryption.
     * @exception InvalidKeyException if one of the following occurs: <ul>
     *                <li> key.getEncoded() == null;
     *                <li> The length of the user key array is not KEY_LENGTH.
     *              </ul>
     */
    protected void engineInitEncrypt (Key key)
    throws InvalidKeyException, CryptixException {
        makeKey(key);
    }

    /**
     * <b>SPI</b>: Initializes this cipher for decryption, using the
     * specified key.
     *
     * @param  key  the key to use for encryption.
     * @exception InvalidKeyException if one of the following occurs: <ul>
     *                <li> key.getEncoded() == null;
     *                <li> The length of the user key array is not KEY_LENGTH.
     *              </ul>
     */
    protected void engineInitDecrypt (Key key)
    throws InvalidKeyException, CryptixException {
        makeKey(key);