Enigma, ULTRA and U534


By Michael Hörenberg

Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park.

Many of the U534 Enigma messages can be found in the DEFE3 documents, published by the The National Archives (Digital-Microfilm). All information regarding the National Archive are published under the Open Government Licence OGLv2.0 (Crown Licence).

The DEFE3 files: "File copies of teleprinter messages. The various series of messages are of two distinct types: intercepted signals, decrypted, translated, and sent from the German Naval Section of the Admiralty's Naval Intelligence Division at Bletchley Park to the division's Operational Intelligence Centre in the Admiralty; and summaries of intelligence derived from such signals sent to the War Office, Air Ministry and overseas commands. These signals became known as ULTRA." (Source: The National Archives)

We are in the fortunate position to present to you original naval Enigma M4 radio messages and the corresponding Ultra decrypts. As you can see at the time stamp, it took between one day and several days until Blechley had decrypted a message.

TOO: Time Of Origin (transmitted by the Germans without encryption. This information determined the daily Enigma key to use).
TOI: Time Of Interception
Footnote: Time of Transmission
4600 KC/S = 4600 Kilo Cycles per Second. Transmitted via shortwave (4,6 MHz).


U534 Enigma decrypts (some examples, we found much more):


Image "Ultra Enigma message"
DEFE 3/577 Page 750
ULTRA document: DEFE 3/577 Page 750

Original Plaintext of P1030660:

FXDXUUUOSTYFUNCQUUUFXWTTXVVVUUUEINSEINSNULDREIKKEISELEKKXXISTSECHSSTUENDLICHESDOCKENVORMITTAGSAMDREIXFUNFXINRENDSBURGGEMXFXDXUUUOSTMOEGLICHL

[An] F.d.U. Ost, 5.U-Flott. von U-1103 (Eisele): Ist sechsstündliches docken vormittags am 3.5. in Rendsburg gemäß F.d.U. Ost möglich?



Image "Government Code and Cypher School message"
DEFE 3/577 Page 765
ULTRA document: DEFE 3/577 Page 765

Original Plaintext of P1030662:

UUUVIRSIBENNULEINSYNACHRXUUUSTUETZPUNKTLUEBECKVVVCHEFVIERXUUUFLOTTXXMITUUUVIERSIBENNULZWOUNDUUUVIERSIBENNULDREIZURFLENDERWERFTLUEBECKGEHENXFONDORTFOLGTWEITERESX

[An] U-4701, nachrichtlich [an] U-Stützpunkt Lübeck von Chef 4. U-Flottille: Mit U-4702 und U-4703 zur Flender Werft Lübeck gehen. Von dort folgt Weiteres.



Image "Enigma Ultra Dokument"
DEFE 3/577 Page 823
ULTRA document: DEFE 3/577 Page 823

Original Plaintext of P1030669:

SSDCHEFFUNFXUUUFLOTTXXEINSKKTTTFFFEINSACHTMITZWOSTELLKARTENAUSRUESTUNGSKAGERRAKUNDNORWEGENMITHAFENPLAENENUNDEINSEXEMPLARLFDXBEFXBBBDDDUUUOOOPPPNRXSIEBENVOMZWOVIERXVIERXVIERFUNFXSOFORTNEUSTADTINMARSCHSETZENXZWOKKTTTFFFEINBNEUNVORLPEUFIGKIELBLEIBENXDHEIKKBESTARTEHXNGERBETENXXFXDXUUUAUSBXKF

SEHR SEHR DRINGEND [An] Chef 5. U-Flott:
1) Torpedofangboot 18 mit 2 Stellkarten Ausrüstung Skagerrak und Norwegen mit Hafenplänen und 1 Exemplar laufende Befehl B.d.U. Op. Nr. 7 vom 24.4.45. sofort Neustadt in Marsch setzen.
2) Torpedofangboot 19 vorläufig Kiel bleiben.
3) Bestätigung erbeten.

[Von] F.d.U. Ausb.




Image "Bletchley Park Enigma decrypt"
DEFE 3/577 Page 744
ULTRA document: DEFE 3/577 Page 744

Original Plaintext of P1030672:

FXDXUEUOSTKKINGXKKVONVONUUUEINSEINSNULDREIKKEISELEKKXXEINSKKUNDICHTIGKEITROHRVIERXKKBEYYUNDENTWAESSERUNGKKZWOKKSCHWEISSENKUEHLWASXERLEITUNGINVIERBACKBORDLBQ

[An] F.d.U. Ost "(Ing.)" von U-1103 "(Eisele)":
1) Undichtigkeit Rohr 4. (Be- und Entwässerung).
2) Schweissen Kühlwasserleitung in 4 [Backbord]. (LBQ)



Image "ULTRA Enigma message from GC&CS"
DEFE 3/578 Page 722
ULTRA document: DEFE 3/578 Page 722

Original Plaintext of P1030673:

FUENFTEUUUFLOTTXANANUUUZWOFUEDFEINSSIEBENXXSPEZIAHISTFUERTELEKINANLAGEWARTEAUFUUULEITSTELLEXFRAGEXXWANNWIRDSPEZIALISTABGEHOLTXBN

[Von] Fünfte U-Flottille an U-2517: Spezialist für Telekin Anlage warte auf U-Leitstelle. Frage: Wann wird Spezialist abgeholt? (XBN)



Also the end of U534 is documented in the ULTRA files:

Image "The end of German submarine U534 Part 1"
DEFE 3/744 Page 38
The End of U534 Part1.

Image "The end of German submarine U534 Part 2"
DEFE 3/744 Page 36
The End of U534 Part2.

Image "The end of German submarine U534 Part 3"
DEFE 3/744 Page 55
The End of U534 Part3.