Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!wuarchive!psuvax1!rutgers!att!cbnews!military From: pierson@cimnet.enet.dec.com (LAY ON GROUND. LIGHT FUZE. 10-Oct-1990 1834) Newsgroups: sci.military Subject: Enigma, ULTRA and history Message-ID: <1990Oct11.050958.29611@cbnews.att.com> Date: 11 Oct 90 05:09:58 GMT Sender: military-request@att.att.com Organization: AT&T Bell Laboratories Lines: 42 Approved: military@att.att.com From: "LAY ON GROUND. LIGHT FUZE. 10-Oct-1990 1834" Looked, couldn't find the reference for this... The Poles, ca 1935, broke into a German diplomatic shipment, found an Enigma on its way to the German Embassy in Russia. As war was likely, they got all the necessary info, carefully reassembled the shipment, and sent it along. (this is known in the crypto biz as "practical cryptography" == steal the keys and or equipment). Having built some machines, and done some analysis, the Poles built an initial mechanical aid, in the form of perforated sheets of heavy paper, representing rotor wiring with openings, and a light box, to help with key recovery. This approach came to be known as a "bombe". With relatively infrequent key changes, it sufficed. When Poland was overrun, the techniques, pieces an analysis went first to France, then to the UK. By now, the massive number of circuits being monitored, and the increased frequency of key change, led to the introduction of the "proto computers" to aid in key recovery. (Its not clear that the Colossus proto computer was used against Enigma...). The Allies were aided by additional practical cryptography, and sloppy technique by German operators. (keys like AAAAA and ABCDE were usually tried first, and recovered much traffic. Additionally, since it was used throughout the German forces, the same message could be (and was) encountered in different keys, leading to additional break-ins. Kahn's "The Codebreakers" is a good book, the hardcover (used book stores...) is unabridged. It suffers from having been written "just" before the lid came off the ULTRA/Enigma penetration. Gordon Welchman's "The Hut Six Story" is one of the more technical books out on the ULTRA/Enigma penetration. thanks dave pierson |the facts, as accurately as i can manage, Digital Equipment Corporation |the opinions, my own. 600 Nickerson Rd Marlboro, Mass 01752 pierson@cimnet.enet.dec.com "He has read everything, and, to his credit, written nothing." A J Raffles