In order to remove a newly discovered weakness in the cipher, a slight change is required in the Handycipher encryption and decryption algorithms. In two weeks three new challenges, Handycipher Parts 7, 8. and 9, will be offered duplicating Parts 4, 5, and 6 with new plaintexts but using the strengthened cipher.
At that time Handycipher Parts 3 - 6 as well as Extended Handycipher Parts 4 - 6 will be reassigned from Level III to Level II, because the changes made to the algorithms will call attention to the weakness which significantly reduces the level of difficulty. Handycipher Part 9 will then be the sole Level III challenge in the series.