20037980 story Convicted Terrorist Relied On Single-Letter Cipher 254 Posted by timothy on Friday April 01, 2011 @05:23AM from the was-the-letter-q? dept. Hugh Pickens writes "The Register reports that the majority of the communications between convicted terrorist Rajib Karim and Bangladeshi Islamic activists were encrypted with a system which used Excel transposition tables which they invented themselves. It used a single-letter substitution cipher invented by the ancient Greeks that had been used and described by Julius Caesar in 55BC. Despite urging by the Yemen-based al Qaida leader Anwar Al Anlaki, Karim rejected the use of a sophisticated code program called 'Mujhaddin Secrets' which implements all the AES candidate cyphers, 'because "kaffirs," or non-believers, know about it so it must be less secure.'"