U-boat's Enigma Cracked With PCs

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March 03, 2006 (12:22 PM EST)

By Gregg Keizer , TechWeb Technology News

Sixty years after the end of World War II, a network of several thousand PCs has cracked a message enciphered with the famous Enigma machine.

The M4 Message Breaking Project, started by Stefan Krah, a German amateur cryptographer, in January, took on three messages intercepted by British code-breakers during WWII, but never cracked by the famous cryptology facility at Bletchley Park.

The code breakers at Bletchley included computing pioneer Alan Turing and used a combination of human intelligence, guesswork, and elementary computing, called "bombs" to decipher messages."

At various times, Bletchley Park could read virtually all Enigma-ciphered messages to and from U-boats at sea, which was instrumental in locating and sinking the submarines, or steering convoys away from U-boat wolfpacks.

The three messages were enciphered using the vaunted Enigma, a machine that relied on a series of user-set rotors and an accompanying plugboard to encrypt text messages before they were radioed from U-boats in the North Atlantic to the German navy's headquarters ashore.

In January, Krah's Web site posted Unix and Windows versions of an open-source client that runs in the background on each machine. As in other distributed-computing projects -- such as the one recently started by the BBC to help model climate change -- the message-breaking chore was broken into small pieces, then parceled out to individual machines that had installed the software.

On Feb. 20, Krah announced that the first message had been broken.

The Enigma-enciphered message, which looked like this:

NCZWV USXPN YMINH ZXMQX SFWXW LKJAH SHNMC
OCCAK UQPMK CSMHK SEINJ USBLK IOSXC KUBHM
LLXCS JUSRR DVKOH ULXWC CBGVL IYXEO AHXRH
KKFVD REWEZ LXOBA FGYUJ QUKGR TVUKA MEURB
VEKSU HHVOY HABCJ WMAKL FKLMY FVNRI ZRVVR
TKOFD ANJMO LBGFF LEOPR GTFLV RHOWO PBEKV
WMUQF MPWPA RMFHA GKXII BG

Actually read, said Krah:

"F T 1132/19 Inhalt:
Bei Angriff unter Wasser gedr�ckt.
Wabos. Letzter Gegnerstand 0830 Uh
r AJ 9863, 220 Grad, 8 sm. Stosse nach.
14 mb. f�llt, NNO 4, Sicht 10.
Looks"

And was translated into English to:

"F T 1132/19 contents:
Forced to submerge during attack.
Depth charges. Last enemy position 0830h
AJ 9863, [course] 220 degrees, [speed] 8 knots.
[I am] following [the enemy].
[barometer] falls 14 mb, [wind] nor-nor-east,
[force] 4, visibility 10 [nautical miles].
Looks"

Hartwig Looks, the captain of the U-264, was among the 52 survivors of a depth charge attack by two British sloops, the HMS Woodpecker and HMS Starling, on Feb. 19, 1944.

So far, several runs have been completed against one of the other messages, but with no success. "This does not mean that this particular message can't be broken with this method," Krah wrote on the project's blog. "Some messages require many more walks through the search space before a break occurs."

Currently, about 5,000 computers are participating in the project. Users who want to install the distributed-computing client can find it on the M4 Web site.