private void rot13(CharBuffer cb) {
		for (int pos = cb.position(); pos < cb.limit(); pos++) {
			char c = cb.get(pos);
			char a = '\u0000';
			// Is it lowercase alpha?
			if ((c >= 'a') && (c <= 'z')) {

				a = 'a';
			}
			// Is it uppercase alpha?
			if ((c >= 'A') && (c <= 'Z')) {
				a = 'A';
			}
			// If either, roll it by 13
			if (a != '\u0000') {
				c = (char) ((((c - a) + 13) % 26) + a);
				cb.put(pos, c);
			}
		}
	}