/**
* Process the <em>Clear</em> part of the message.
*
* @param in a byte array containing the <em>Clear</em> part of the message.
* @param offset the starting index in <code>in</code> where the <em>Clear</em> message bytes
* should be considered.
* @param length the count of bytes in <code>in</code>, starting from <code>offset</code> to
* consider.
* @throws IllegalStateException if no start-of-message method has been invoked earlier or the
* Integrity Protection service has not been activated.
*/
public void doClear(byte[] in, int offset, int length) {
if (!ready) {
throw new IllegalStateException();
}
if (!wantIntegrity) {
throw new IllegalStateException();
}
mac.update(in, offset, length);
}
/**
* Process the <em>Opaque</em> part of the message.
*
* @param in a byte array containing the <em>Clear</em> part of the message.
* @param inOffset the starting index in <code>in</code> where the <em>Opaque</em> message bytes
* should be considered.
* @param length the count of bytes in <code>in</code>, starting from <code>inOffset</code> to
* consider.
* @param out the byte array where the enciphered opaque message should be stored.
* @param outOffset the starting offset in <code>out</code> where the enciphered bytes should be
* stored.
* @throws IllegalStateException if no start-of-message method has been invoked earlier.
* @throws LimitReachedException if one or both of the underlying keystream generators have
* reached their limit.
*/
public void doOpaque(byte[] in, int inOffset, int length, byte[] out, int outOffset)
throws LimitReachedException {
if (!ready) {
throw new IllegalStateException();
}
if (wantIntegrity) {
mac.update(in, inOffset, length);
}
if (wantConfidentiality) {
byte[] suffix = new byte[length];
cpStream.nextBytes(suffix, 0, length);
for (int i = 0; i < length; ) {
out[outOffset++] = (byte) (in[inOffset++] ^ suffix[i++]);
}
} else {
System.arraycopy(in, inOffset, out, outOffset, length);
}
}
