Decrypt Fragments

These documents are working papers used at Bletchley Park in or around 1945. Some documents contain ciphertext which needed to be decrypted, while others contain partial decrypts which needed to be cleaned up. Several of the documents seem to have been used at Hut 3.

Enigma message decrypt
Decrypt. Message from Berlin to General Kurland.
Enigma message decrypt
Small scraps from Hut 3
Enigma message decrypt
Decrypt fragment
Enigma message decrypt
Decrypt fragment
Enigma message decrypt
Ciphertext on front, and...
Enigma message decrypt
...decrypt on the reverse side.
Enigma message decrypt
Ciphertext on front, and...
Enigma message decrypt
...decrypt on the reverse side.
Enigma message decrypt
Ciphertext
Enigma message decrypt
Decrypt fragment
Enigma message decrypt
Decrypt fragment
Enigma message decrypt
Decrypt fragment
Enigma message decrypt
Decrypt fragment
Enigma message decrypt
Decrypt fragment
Enigma message decrypt
Decrypt fragment

 

I would like to thank David Hamer, the owner of these documents, for giving me permission to publish these scans. I would also like to thank Rowena Clough of the National Cryptologic Museum for her assistance.

Geoff Sullivan was kind enough to provide this additional information on these decrypts:

The first scan on your Enigma Decrypts page is a Tunny (SZ42) decode, rather than Enigma, from the Whiting link. This was operational June '43 to July' 44. Perhaps David did not say so. I did not know any of these papers existed. Hut 3 would be the people to work on translating and process these army messages, rather than cryptanalysis, which was done in Newmanry and Testery.

These are fascinating documents, I now see where they came from. I don't think there are any over here. I have seen a few transcripts but never an original printout.

Looking at the scans a little closer, it seems they are all Tunny decrypts except for the two Jaguar key Luftwaffe Enigma messages. These two have TypeX decoded printed tape outputs stuck on the reverse in 5 letter groups.

The Tunny messages would be decrypted, after the message key was fully broken, with Tunny machines which emulated the SZ42. These were built with telephone stepping switches. The output from Tunny went to specially modified Creed teleprinters. These were standard machines modified to print all 32 of the 5 bit Baudot codes. The usual 'non printing' characters space, linefeed, carriage return, figure shift, letter shift, null were printed as . 4 3 + - and / respectively. You can see an example of the figures output on the first scan, fifth line. The sequence is .++.QPUWO.QEMWM.QPPP which is space, number shift, number shift, space followed by the numbers from the top row of the keyboard (Q=1, W=2, E=3 etc.). Hut 3 have written the number in pencil below (10721 13.3 1000) The reason for the double figures shifts is to keep the machine in step, if a shift character was lost in transmission, the output would be garbage until the next correct shift character. This repeating of letters was part of the downfall of the machine, allowing breaking of single bit streams by the delta metdod. You can see other examples of penciled in shifted characters; K = open bracket, L = close bracket and M = dot (period).

The red annotation on the top of the form is Berlin to H. Gr. Kurland :- Berlin to Heeresgruppe Kurland (Army Group Courland). I believe this was related to the Russian front around Latvia. The Tunny key is Whiting.

Transmission started at 08:57 (TS 08:57) and ended at 09:45 (TE 9:54), on the frequency 7691 KHz., which would be around 15-20,000 characters at the speed of 50 Baud. This looks about right if the message printout is 23 pages. It could possibly be one or more messages on a single paper tape run. Messages would be sent through in largish batches when the frequency channel was open. The modified teleprinters only printed the 32 characters in response to the electrical signal input, the operator would need to add the line-feeds manually by watching the output and typing on the keyboard when the line was full. As you see there are a lot of abbreviations, most of which I don't understand (but Frode probably would). I can see Hungary and Croatia mentioned near the bottom of the page.