Nazi code is cracked after 60 years

Published on Friday 3 March 2006 01:49

THE Nazi code which sent thousands of allied sailors to their deaths in the Second World War has been cracked more than 60 years after Britain's best mathematical minds failed to break it.

The Enigma code was the most complex cipher system of its age and virtually foolproof.

The wartime prime minister, Winston Churchill, ordered the greatest minds of the day to work at Bletchley Park to decipher Enigma, which gave the orders to "wolf packs" of U-boats in the Atlantic to sink the merchant shipping keeping Britain going.

All the codes except three were broken. Now, the work of a German amateur cryptographer has led to the solving of one of the three unresolved Enigma puzzles dating from 1942.

Seemingly random ranks of letters took on a clear meaning by running code-breaking software on a "grid" of internet-linked home computers.

The three unsolved Enigma intercepts were published in a cryptography journal in 1995 and have intrigued enthusiasts ever since.

The latest attempt to crack the codes was launched by Stefan Krah, a violinist with an interest in cryptography.

Enigma was a cipher machine with numerous settings. U-boats had one on board and their shore-based commanders had others which, with a spin of a rotor and a plug into an electrical circuit, could come up with seemingly infinite permutations.

Britain got lucky when one was snatched from a sinking U-boat early in the war. But the German naval high command regularly changed the codes.

Bletchley Park codebreakers were in a perpetual race against time to get ships into position to protect convoys from hunting packs of German submarines.

Mr Krah wrote a codebreaking computer program and publicised his project on internet newsgroups, attracting the interest of about 45 enthusiasts.

He named the project M4, in honour of the M4 Enigma machine that originally encoded the ciphers.

In a little over a month the message had been decoded into a real wartime communication.

A check against existing records confirmed that the message was sent by Kapitanleutnant Hartwig Looks, commander of the U264 submarine, on 25 November, 1942.

Mr Krah said his codebreaking software uses a combination of "brute force" and complex maths to get at the truth.

Sea battle drama hidden in letters

In its encrypted form the cipher makes no sense at all, reading as follows:

"NCZW VUSX PNYM INHZ XMQX SFWX WLKJ AHSH NMCO CCAK UQPM KCSM HKSE INJU SBLK IOSX CKUB HMLL XCSJ USRR DVKO HULX WCCB GVLI YXEO AHXR HKKF VDRE WEZL XOBA FGYU JQUK GRTV UKAM EURB VEKS UHHV OYHA BCJW MAKL FKLM YFVN RIZR VVRT KOFD ANJM OLBG FFLE OPRG TFLV RHOW OPBE KVWM UQFM PWPA RMFH AGKX IIBG"

But deciphered and translated into English, the message suddenly comes to life:

"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]."

The German submarine which sent the message, U-264, was sunk at 17:07hrs on 19 February, 1944 in the North Atlantic, by depth charges from the Royal Navy sloops HMS Woodpecker and HMS Starling, having survived five patrols. All the crew of 52 were rescued.