I'm trying to use the Cipher class and am not understanding allowable key lengths (in init). According to the documentation 128, 192 and 256 bits, among others, should all be valid. When I use a 16 byte string (128 bits) it accepts it as I expected. However, If I try a 24 (192 bits) or 32 byte string (256 bits) I get an InvalidKeyException (Illegal key size or default papameters). What size strings am I allowed to use that are >16 bytes? TIA.