This was  a prequel to what happened  when the Poles  sent an ENIGMA   machine to UK  before the  fall of Poland /With some of the same results  we were reading

German op  messages almost as soon as  they were.

In theory the enigma machine IS (without modern computers)  impossible to decypher. It was only small operator errors and the capture of a handful of codebooks that allowed messages to be decyphered at all.

And as someone here has already pointed out the movie U571 is partly a lie - two RN sailors gave their lives recovering codebooks from the U boat.

Funk

I believe the chink in the armour was no key could send its own number.

 These diagrams, called MENUS, became input programmes for unique machines called BOMBES. This name was originated by three brilliant Polish mathematicians who had achieved limited success in breaking the Enigma codes before Poland was invaded in September 1939. Their names were Marian Rejewski, Jerzy Rozycki and Henryk Zygalski. The reason for choosing this name for their code breaking apparatus is debatable, but the most feasible explanation is that it ticked like a bomb when in operation. The first British bombe was commissioned at Bletchley Park in March 1940. The mathematical logic on which the machine operated was developed by one of the code breakers called Alan Turing

 

 However, in basic terms, this amazing machine was able to test the menus against every possible permutation of Enigma rotor selection and settings at high speed. The 17,576 permutations produced by one set of Enigma rotors could be searched in about 17 minutes.

The purpose of the bombe was to find circuits which would identify positions where the menu matched the rotor sequence and settings for that particular key. High speed sensing relays then stopped the bombe at the relevant settings. However, bombes were constantly being improved and later versions were fitted with an attachment which typed out the letters concerned without stopping the machine.

The bombes functioned for 24 hours per day and 7 days per week. They were operated on a rotating shift system by WRENS (Women’s Royal Naval Service) Each bombe was attended by two Wrens. Before each test run, the menu was ‘plugged up�?to programme the bombe

OK, I can go on and on, but parallel to the capture of enigma codes at sea, which gave us the rotors and their settings, (and were probably the silver bullet we needed) there appears to be a slower more methodical primitive computer development.

Trouble is, Bletchley is very high camp in the entertainment world, all the personalities, their clashes, and all that guff. I doubt the armed forces will ever get proper credit for their captures. (bit like The Battle of Britain film. Who won? Susannah York or the RAF?)

 

Peter 

well  done  funk. we  did capture  enigma  from 2 u bopats  1) U 110  sank  but not befire vrew  from HMS  BULLDOG   had taken enigma  machine & books  and  2)U 570   which was captured  by an RAF  HUDSON a/c  out of Iceland  and they  stayed on top until the RN     showed up and towed it to Iceland. She later became  HMS  GRAPH  and   was scrapped post war