| /* ModeFactory.java -- |
| Copyright (C) 2001, 2002, 2004, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.javax.crypto.mode; |
| |
| import gnu.java.security.Registry; |
| |
| import gnu.javax.crypto.cipher.CipherFactory; |
| import gnu.javax.crypto.cipher.IBlockCipher; |
| |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Set; |
| |
| /** |
| * A <i>Factory</i> to instantiate block cipher modes of operations. |
| */ |
| public class ModeFactory |
| implements Registry |
| { |
| private static Set names; |
| |
| /** Trivial constructor to enforce Singleton pattern. */ |
| private ModeFactory() |
| { |
| super(); |
| } |
| |
| /** |
| * Returns an instance of a block cipher mode of operations given its name and |
| * characteristics of the underlying block cipher. |
| * |
| * @param mode the case-insensitive name of the mode of operations. |
| * @param cipher the case-insensitive name of the block cipher. |
| * @param cipherBlockSize the block size, in bytes, of the underlying cipher. |
| * @return an instance of the block cipher algorithm, operating in a given |
| * mode of operations, or <code>null</code> if none found. |
| * @exception InternalError if either the mode or the underlying block cipher |
| * implementation does not pass its self-test. |
| */ |
| public static IMode getInstance(String mode, String cipher, |
| int cipherBlockSize) |
| { |
| if (mode == null || cipher == null) |
| return null; |
| |
| mode = mode.trim(); |
| cipher = cipher.trim(); |
| IBlockCipher cipherImpl = CipherFactory.getInstance(cipher); |
| if (cipherImpl == null) |
| return null; |
| |
| return getInstance(mode, cipherImpl, cipherBlockSize); |
| } |
| |
| public static IMode getInstance(String mode, IBlockCipher cipher, |
| int cipherBlockSize) |
| { |
| // ensure that cipherBlockSize is valid for the chosen underlying cipher |
| boolean ok = false; |
| for (Iterator it = cipher.blockSizes(); it.hasNext();) |
| { |
| ok = (cipherBlockSize == ((Integer) it.next()).intValue()); |
| if (ok) |
| break; |
| } |
| if (! ok) |
| throw new IllegalArgumentException("cipherBlockSize"); |
| IMode result = null; |
| if (mode.equalsIgnoreCase(ECB_MODE)) |
| result = new ECB(cipher, cipherBlockSize); |
| else if (mode.equalsIgnoreCase(CTR_MODE)) |
| result = new CTR(cipher, cipherBlockSize); |
| else if (mode.equalsIgnoreCase(ICM_MODE)) |
| result = new ICM(cipher, cipherBlockSize); |
| else if (mode.equalsIgnoreCase(OFB_MODE)) |
| result = new OFB(cipher, cipherBlockSize); |
| else if (mode.equalsIgnoreCase(CBC_MODE)) |
| result = new CBC(cipher, cipherBlockSize); |
| else if (mode.equalsIgnoreCase(CFB_MODE)) |
| result = new CFB(cipher, cipherBlockSize); |
| else if (mode.equalsIgnoreCase(EAX_MODE)) |
| result = new EAX(cipher, cipherBlockSize); |
| |
| if (result != null && ! result.selfTest()) |
| throw new InternalError(result.name()); |
| |
| return result; |
| } |
| |
| /** |
| * Returns a {@link Set} of names of mode supported by this <i>Factory</i>. |
| * |
| * @return a {@link Set} of mode names (Strings). |
| */ |
| public static final Set getNames() |
| { |
| synchronized (ModeFactory.class) |
| { |
| if (names == null) |
| { |
| HashSet hs = new HashSet(); |
| hs.add(ECB_MODE); |
| hs.add(CTR_MODE); |
| hs.add(ICM_MODE); |
| hs.add(OFB_MODE); |
| hs.add(CBC_MODE); |
| hs.add(CFB_MODE); |
| hs.add(EAX_MODE); |
| names = Collections.unmodifiableSet(hs); |
| } |
| } |
| return names; |
| } |
| } |