Expansion and consolidation (June 1941 - January 1943)

Hut 6 story

Introduction

The number of keys to manage increases significantly. Fortunately the personnel of Hut 6 and the number of bombes increases accordingly thanks to the characters in charge of Hut 6 and 8 (cf. Action this day).

On the other hand, the structure of Hut 6 is completely renewed.

The bombes are still few and are shared with the hut 8 responsible for breaking the keys of the navy.

Finally, although the first re-encoding (called "kissing") date from March 1941, it is during this period that they become frequent.

The war

The great event of this period is the opening of a second front with Operation Barbarossa, that is to say the invasion by Hitler of the Soviet Union in June 1941.

As for the campaign in North Africa, the fighting rages on but after a whole series of battles, Romel suffers a major defeat at El Alamen in October 1942. In November 1942, the USA landed in North Africa in the United States at west and therefore take in pincers the German forces.

The keys

The number of keys processed by hut 6 explodes. We went from a dozen keys in June 1941 to more than 60 in January 1943. The colors were no longer sufficient, hut 6 used bird names, for example Chaffinch, Vulture, kestrel (for army keys air), insects, flowers, ...

Action this Day

The Hut 6 and 8, responsible for decrypting the Enigma, were enjoying increasing success but were limited by a lack of personnel and bombes. The requests asking for more ressources followed the hierarchical route (to Denniston, the director of CG&CS) did not appear to be successful.

The leaders (directors and deputy directors) of the two Huts (Turing, Alexander, Welchman, Milner-Barry) send a letter asking for means directly to Churchill, who some time before had visited BP. Stuart Miler-Barry is responsible for delivering the letter to 10 Downing Street.

On receiving the letter, Churchill minuted his Chief of Staff: ‘action this day. Make sure they have all they want on extreme priority and report to me that this had been done.’

Organization

During this period, Hut 6 becomes more complex.

As from the start, there is always the RR and DR sections.

  • The RR (Registration Room) which records messages from Y-stations and sorts them according to their network of belonging (according to frequencies, kenngruppe, etc.).
  • The DR (Decipher Rool) which decrypts the messages when the key has been found.

As in the previous period, the heart of the Hut are the CR and MR sections:

  • The CR (Crib Room) which searches for and positions the cribs.
  • The MR (Machine Room) prepares the menus for the bombes and tests the stops that occur and finishes finding the other elements of the key (all the steckers, the ringstellung).

But over time, these sections will be duplicated:

  • CR1 and MR1 which deal with operational keys.
  • CR2 and MR2 which deal with keys which are not operational, ie which are not yet broken. They correspond to the old "Research" section.
  • We will even have an RR2 section.

It is also during this period that the school appears to train new staff as well as the Control Room.

The Control Room, in conjunction with the Y-Stations and Hut 3, checks that the important radio frequencies (from an intelligence or cryptographic point of view) are duplicated.

The staff

Derek Taunt joined BP in August 1941. At the time, the director of Hut 6 is still Gordon Welchmen, its founder. The deputy director is Stuart-Milner Barry who is a friend of Gordon, he is responsible for sections CR1 and CR2. Dennis Babbage is in charge of the MR1 and MR2 sections. Among the "old men" there is also Dr James Aitken, a Scottish chess player.

Bombes (3 rotors)

  • 1941 December : 12
  • 1942 December : 40

References