public static String getHex( byte [] raw ) {
	    if ( raw == null ) {
	      return null;
	    }
	    final StringBuilder hex = new StringBuilder( 2 * raw.length );
	    for ( final byte b : raw ) {
	      hex.append(HEXES.charAt((b & 0xF0) >> 4))
	         .append(HEXES.charAt((b & 0x0F)));
	    }
	    return hex.toString();
	}