The History of Hut Eight

traffic from the South of France and there had been some very useful reencodements into Porpoise, notably of a long situation report. This now disappeared so that it was no longer true to say that if either Porpoise or Dolphin could be broken, the other should give little trouble.

September was a somewhat chaotic month and brought various cryptographic troubles. Narwhal began as an independent 4 wheel key and had to be broken regularly. At first there were reencodements from Dolphin but these soon died and we were dependent on weather and reencodements from Shark: Shark also suffered as Narwhal was less frequently current and in a position to supply reencodements. At the same time Bonito abandoned the throw-on system and was giving considerable trouble. The crib position on Dolphin also was not very secure and it was a great relief when keys began to be sent to the Channel Islands in Dolphin messages on the keys of August: this lasted for most of the first half of the month and shortly afterwards keys for the whole month were captured at Brest. On the 17th Dolphin split into 2 groups using different Stichworts, 1 group being the Channel area, the other the North Sea and Norwegian Area. Fearing a compromise, the Germans on the 23rd split Dolphin into 3; the Channel Area used August keys in a hatted order (Dolphin 1); the Norwegian and North Sea area used October keys with a Stichwort (Dolphin II) and a third area (Tuegingen-Muensingen) used October keys with an independent Stichwort (Dolphin 2A). Dolphin II was broken regularly on reencodements from Dolphin 1. At the end of the month October wheel orders for the whole month were sent to the Channel Islands, but the Stecker for only 5 days: the rest of the keys are believed to have reached the Channel Islands by air. Dolphin 1 continued to use August keys in October and was rechristened Sucker, Dolphin II became Dolphin and Dolphin IIA, soon to disappear, Dolphin A. Sucker became at this time the key of the Channel fortresses.

On October 1st the disintegration of keys continued and Porpoise split into 3 groups. The Italian group retained the name Porpoise, the Adriatic was christened Bloater, the Aegean Catfish. Catfish reused September keys and was decoded currently until December 15th when an independent key was set up; by this time there was little traffic and none of any significance and no attempt was made to break the new key. Bloater used a rehash of September keys until November 15th when all except one small group of traffic went onto a separate key. Through lack of bombe time and lack of interest in its contents this independent key was never broken but on January 12th 1945 it merged with Porpoise: this very convenient development was almost without precedent as keys had frequently split but, with the exception of Laube and Dolphin, never merged.

Porpoise proper used October keys and fared much less well


< previous

next >