public void fillBlock() throws LimitReachedException {
cipher.encryptBlock(buffer, 0, buffer, 0);
}
public void setup(Map attributes) {
boolean newCipher = true;
String cipherName = (String) attributes.get(CIPHER);
if (cipherName == null) {
if (cipher == null) { // happy birthday
cipher = CipherFactory.getInstance(Registry.RIJNDAEL_CIPHER);
} else { // we already have one. use it as is
newCipher = false;
}
} else {
cipher = CipherFactory.getInstance(cipherName);
}
// find out what block size we should use it in
int cipherBlockSize = 0;
Integer bs = (Integer) attributes.get(IBlockCipher.CIPHER_BLOCK_SIZE);
if (bs != null) {
cipherBlockSize = bs.intValue();
} else {
if (newCipher) { // assume we'll use its default block size
cipherBlockSize = cipher.defaultBlockSize();
} // else use as is
}
// get the key material
byte[] key = (byte[]) attributes.get(IBlockCipher.KEY_MATERIAL);
if (key == null) {
throw new IllegalArgumentException(IBlockCipher.KEY_MATERIAL);
}
int keyLength = key.length;
// ensure that keyLength is valid for the chosen underlying cipher
boolean ok = false;
for (Iterator it = cipher.keySizes(); it.hasNext(); ) {
ok = (keyLength == ((Integer) it.next()).intValue());
if (ok) {
break;
}
}
if (!ok) {
throw new IllegalArgumentException("key length");
}
// ensure that remaining params make sense
int index = -1;
Integer i = (Integer) attributes.get(INDEX);
if (i != null) {
index = i.intValue();
if (index < 0 || index > 255) {
throw new IllegalArgumentException(INDEX);
}
}
// now initialise the underlying cipher
Map map = new HashMap();
if (cipherBlockSize != 0) { // only needed if new or changed
map.put(IBlockCipher.CIPHER_BLOCK_SIZE, new Integer(cipherBlockSize));
}
map.put(IBlockCipher.KEY_MATERIAL, key);
try {
cipher.init(map);
} catch (InvalidKeyException x) {
throw new IllegalArgumentException(IBlockCipher.KEY_MATERIAL);
}
buffer = new byte[cipher.currentBlockSize()];
buffer[cipher.currentBlockSize() - 1] = (byte) index;
try {
fillBlock();
} catch (LimitReachedException impossible) {
}
}
