BA jihadist relied on Jesus-era encryption • The Register
(thanks to Bruce Schneier's blog for the reference)
CS students, take note. These terrorists thought that they would be clever and invent a cryptographic system that no-one else knew about, and therefore couldn't be cracked. No need to use all these algorithms like AES which are public ... the secrecy of their algorithm would protect them.
What they ended up accomplishing was re-inventing the Caesar Cipher, dating back to 55 BC, which is trivially easy to break. It looked a lot more fancy, apparently using a bunch of Excel tables to make it look all 21st century. But the net result was the same; a code that was breakable by even the poorest CS student.