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Diffstat (limited to 'gnu/javax/crypto/mode/BaseMode.java')
| -rw-r--r-- | gnu/javax/crypto/mode/BaseMode.java | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/gnu/javax/crypto/mode/BaseMode.java b/gnu/javax/crypto/mode/BaseMode.java new file mode 100644 index 000000000..0a9ab2dab --- /dev/null +++ b/gnu/javax/crypto/mode/BaseMode.java @@ -0,0 +1,352 @@ +/* BaseMode.java -- + Copyright (C) 2001, 2002, 2003, 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.javax.crypto.cipher.IBlockCipher; + +import java.security.InvalidKeyException; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.HashMap; +import java.util.Iterator; +import java.util.Map; + +/** + * <p>A basic abstract class to facilitate implementing block cipher modes of + * operations.</p> + */ +public abstract class BaseMode implements IMode +{ + + // Constants and variables + // ------------------------------------------------------------------------- + + /** The canonical name prefix of this mode. */ + protected String name; + + /** The state indicator of this instance. */ + protected int state; + + /** The underlying block cipher implementation. */ + protected IBlockCipher cipher; + + /** The block size, in bytes, to operate the underlying block cipher in. */ + protected int cipherBlockSize; + + /** The block size, in bytes, in which to operate the mode instance. */ + protected int modeBlockSize; + + /** The initialisation vector value. */ + protected byte[] iv; + + /** The instance lock. */ + protected Object lock = new Object(); + + // Constructor(s) + // ------------------------------------------------------------------------- + + /** + * <p>Trivial constructor for use by concrete subclasses.</p> + * + * @param name the canonical name prefix of this mode. + * @param underlyingCipher the implementation of the underlying cipher. + * @param cipherBlockSize the block size, in bytes, in which to operate the + * underlying cipher. + */ + protected BaseMode(String name, IBlockCipher underlyingCipher, + int cipherBlockSize) + { + super(); + + this.name = name; + this.cipher = underlyingCipher; + this.cipherBlockSize = cipherBlockSize; + state = -1; + } + + // Class methods + // ------------------------------------------------------------------------- + + // Instance methods + // ------------------------------------------------------------------------- + + // IMode interface implementation ------------------------------------------ + + public void update(byte[] in, int inOffset, byte[] out, int outOffset) + throws IllegalStateException + { + synchronized (lock) + { + switch (state) + { + case ENCRYPTION: + encryptBlock(in, inOffset, out, outOffset); + break; + case DECRYPTION: + decryptBlock(in, inOffset, out, outOffset); + break; + default: + throw new IllegalStateException(); + } + } + } + + // IBlockCipher interface implementation ----------------------------------- + + public String name() + { + return new StringBuffer().append(name).append('(').append(cipher.name()).append( + ')').toString(); + } + + /** + * <p>Returns the default value, in bytes, of the mode's block size. This + * value is part of the construction arguments passed to the Factory methods + * in {@link ModeFactory}. Unless changed by an invocation of any of the + * <code>init()</code> methods, a <i>Mode</i> instance would operate with + * the same block size as its underlying block cipher. As mentioned earlier, + * the block size of the underlying block cipher itself is specified in one + * of the method(s) available in the factory class.</p> + * + * @return the default value, in bytes, of the mode's block size. + * @see gnu.crypto.mode.ModeFactory + */ + public int defaultBlockSize() + { + return cipherBlockSize; + } + + /** + * <p>Returns the default value, in bytes, of the underlying block cipher + * key size.</p> + * + * @return the default value, in bytes, of the underlying cipher's key size. + */ + public int defaultKeySize() + { + return cipher.defaultKeySize(); + } + + /** + * <p>Returns an {@link Iterator} over the supported block sizes. Each + * element returned by this object is an {@link Integer}.</p> + * + * <p>The default behaviour is to return an iterator with just one value, + * which is that currently configured for the underlying block cipher. + * Concrete implementations may override this behaviour to signal their + * ability to support other values.</p> + * + * @return an {@link Iterator} over the supported block sizes. + */ + public Iterator blockSizes() + { + ArrayList al = new ArrayList(); + al.add(new Integer(cipherBlockSize)); + + return Collections.unmodifiableList(al).iterator(); + } + + /** + * <p>Returns an {@link Iterator} over the supported underlying block cipher + * key sizes. Each element returned by this object is an instance of + * {@link Integer}.</p> + * + * @return an {@link Iterator} over the supported key sizes. + */ + public Iterator keySizes() + { + return cipher.keySizes(); + } + + public void init(Map attributes) throws InvalidKeyException, + IllegalStateException + { + synchronized (lock) + { + if (state != -1) + { + throw new IllegalStateException(); + } + + Integer want = (Integer) attributes.get(STATE); + if (want != null) + { + switch (want.intValue()) + { + case ENCRYPTION: + state = ENCRYPTION; + break; + case DECRYPTION: + state = DECRYPTION; + break; + default: + throw new IllegalArgumentException(); + } + } + + Integer bs = (Integer) attributes.get(MODE_BLOCK_SIZE); + modeBlockSize = (bs == null ? cipherBlockSize : bs.intValue()); + + byte[] iv = (byte[]) attributes.get(IV); + if (iv != null) + { + this.iv = (byte[]) iv.clone(); + } + else + { + this.iv = new byte[modeBlockSize]; + } + + cipher.init(attributes); + setup(); + } + } + + public int currentBlockSize() + { + if (state == -1) + { + throw new IllegalStateException(); + } + return modeBlockSize; + } + + public void reset() + { + synchronized (lock) + { + state = -1; + iv = null; + cipher.reset(); + + teardown(); + } + } + + public boolean selfTest() + { + int ks; + Iterator bit; + for (Iterator kit = keySizes(); kit.hasNext();) + { + ks = ((Integer) kit.next()).intValue(); + for (bit = blockSizes(); bit.hasNext();) + { + if (!testSymmetry(ks, ((Integer) bit.next()).intValue())) + { + return false; + } + } + } + + return true; + } + + // methods to be implemented by concrete subclasses ------------------------ + + public abstract Object clone(); + + /** The initialisation phase of the concrete mode implementation. */ + public abstract void setup(); + + /** The termination phase of the concrete mode implementation. */ + public abstract void teardown(); + + public abstract void encryptBlock(byte[] in, int i, byte[] out, int o); + + public abstract void decryptBlock(byte[] in, int i, byte[] out, int o); + + // own methods ------------------------------------------------------------- + + private boolean testSymmetry(int ks, int bs) + { + try + { + IMode mode = (IMode) this.clone(); + byte[] iv = new byte[cipherBlockSize]; // all zeroes + byte[] k = new byte[ks]; + int i; + for (i = 0; i < ks; i++) + { + k[i] = (byte) i; + } + + int blockCount = 5; + int limit = blockCount * bs; + byte[] pt = new byte[limit]; + for (i = 0; i < limit; i++) + { + pt[i] = (byte) i; + } + byte[] ct = new byte[limit]; + byte[] cpt = new byte[limit]; + + Map map = new HashMap(); + map.put(KEY_MATERIAL, k); + map.put(CIPHER_BLOCK_SIZE, new Integer(cipherBlockSize)); + map.put(STATE, new Integer(ENCRYPTION)); + map.put(IV, iv); + map.put(MODE_BLOCK_SIZE, new Integer(bs)); + + mode.reset(); + mode.init(map); + for (i = 0; i < blockCount; i++) + { + mode.update(pt, i * bs, ct, i * bs); + } + + mode.reset(); + map.put(STATE, new Integer(DECRYPTION)); + mode.init(map); + for (i = 0; i < blockCount; i++) + { + mode.update(ct, i * bs, cpt, i * bs); + } + + return Arrays.equals(pt, cpt); + + } + catch (Exception x) + { + x.printStackTrace(System.err); + return false; + } + } +}
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