Sunday, April 16, 2017


In The American M-209 cipher machine i’ve added notes and I’ve also added some text (analysis of German trigram technique and a list of reports on the Hagelin C-38). 

Friday, April 14, 2017

Article on Vietnamese signals intelligence successes against French and US forces

The very interesting article ‘Cryptography During the French and American Wars in Vietnam by Phan Duong Hieu and Neal Koblitz is available online.

Abstract: After Vietnam's Declaration of Independence on 2 September 1945, the country had to suffer through two long, brutal wars, first against the French and then against the Americans, before finally in 1975 becoming a unified country free of colonial domination. Our purpose is to examine the role of cryptography in those two wars. Despite the far greater technological resources of their opponents, the communications intelligence specialists of the Viet Minh, the National Liberation Front, and the Democratic Republic of Vietnam had considerable success in both protecting Vietnamese communications and acquiring tactical and strategic secrets from the enemy. Perhaps surprisingly, in both wars there was a balance between the sides. Generally speaking, cryptographic knowledge and protocol design were at a high level at the central commands, but deployment for tactical communications in the field was difficult, and there were many failures on all sides.

Sunday, April 9, 2017

A misogynistic mistake!

In The Finnish cryptologic service in WWII I’ve added ‘Head of the diplomatic department was Mary Grashorn’.

Mary Grashorn was mentioned in the essay ‘Finland’s codebreaking in WWII’ by David Kahn. I don’t know how I missed that. 

Tuesday, April 4, 2017

The quest for the missing NAASt 5 reports

During WWII the German Army’s signal intelligence agency operated a number of fixed intercept stations and also had mobile units assigned to Army Groups. These units were called KONA (Kommandeur der Nachrichtenaufklärung - Signals Intelligence Regiment) and each had an evaluation centre, a stationary intercept company, two long range signal intelligence companies and two close range signal intelligence companies.

Each KONA regiment was assigned to an Army group and was responsible for intercepting and decoding enemy traffic. KONA 5 was stationed in Western Europe and their cryptanalytic centre NAASt 5 (Nachrichten Aufklärung Auswertestelle - Signal Intelligence Evaluation Center) worked mainly on the radio traffic of the US and UK forces.

In late 1944 the cryptanalysts of NAAS 5, led by Reinold Weber, built a cryptanalytic device in order to solve the settings of the M-209 device more quickly.

In order to learn more about this device and the way it was used I’ve tried to locate any surviving reports of NAAS 5. According to the TICOM report IF-272 - TAB ‘D’ the following NAAS 5 reports survived the war:

E-Bericht Nr. 1/44 der NAAst 5 dated 10.1.44

E-Bericht Nr. 2/44 der NAAst 5

E-Bericht Nr. 3/44 der NAAst 5 (Berichtszeit 1.4-30.6.44)

E-Bericht 4/44 der NAAst 5 (Berichtszeit 1.7-30.9.44) dated 10.10.44 

E-Bericht der NAAst 5 (Berichtszeit 1.10.44-30.12.44) dated 14.1.45

The first three can be found in the US national archives, collection RG 457 - Entry 9032 - box 22, titled ‘German deciphering reports’.

Unfortunately the last two (covering the second half of 1944) are not there.

I asked NARA if they could locate the missing reports elsewhere in collection RG 457 but they could not. I also requested the reports from the NSA’s FOIA office. In October 2016 they responded that the NAAS 5 reports were included in transfer group TR-0457-2016-0014.

I then contacted the NARA FOIA office and asked for the release of the NAAS 5 reports. 

The material in transfer group TR-0457-2016-0014 was classified so they would have to locate the reports and then review them for declassification. Unfortunately they have checked the files several times and they cannot locate any file titled E-Bericht NAAst 5.

So at this time I am trying to find a solution with the NSA and NARA FOIA office.

In the meantime if you know more about this case, if you think you have a better chance of locating the missing reports etc give it a try. 

Friday, March 24, 2017

The Abwehr’s Enigma G cipher machine and Procedure 63

The Cryptologia article Mr. Twinn’s bombes is available from the Taylor and Francis website and it has some very interesting information on the Enigma G cipher machine, used in WWII by the German military intelligence service Abwehr.

The Enigma G was different from the version used by the German military since it did not have a plugboard. Also its stepping was more frequent due to the many notches in the rotors.

According to the article it was used by the following Abwehr networks:

1). Berlin, Madrid, Lisbon, Paris, Bordeaux

2). Berlin, Vienna, Budapest, Bucharest, Sofia, Salonika

3). Berlin, Vienna

4). Berlin with stations in Turkey

The device was issued with 3 rotors only (while the military version used 3 rotors from a set of 5). In some networks the rotors were rewired during the war.

Several indicator systems were used in the period 1941-44. Up to August 1942 the message key was enciphered twice on the Grundstellung (basic setting). The 8 letter sequence was the indicator at the start of the message. This was the same procedure used up to 1938 by the German Army and Airforce.

From August 1942 the double encipherment of the message key was dropped and instead it was enciphered on the Grundstellung only once.

In the period late 1943-early 1944 a new indicator procedure was introduced. This was part of new security regulations called Procedure 63 - ‘Verfahren 63’. The new system used two basic settings. One for the network and one for the station. The cipher clerk first enciphered the message key twice on the network’s basic setting and then enciphered the 8 letters again at the station’s basic setting.

It is interesting to note that an OKW/Chi report dated August 1944 says that Procedure 63 was not secure:

D) Agentenverkehr

Die Vorschrift Nr.63 genügt nur dann zeitgemässen Sicherheitsansprüchen, wenn auf jeder Linie nur wenig Verkehr auftritt. Es soll versucht werden eine bessere Vorschrift auszuarbeiten.

Es wird dafür gesorgt werden, dass alle anderen mit Enigma-Maschinen arbeitenden Behörden usw. nur die vom Ausschuss geprüften und zugelassenen Vorschriften benutzen.

Google translation:

D) Agent traffic

Regulation No.63 only meets current safety requirements if only little traffic occurs on each line. A better regulation is to be worked out.

It is necessary to ensure that all other authorities working with Enigma machines, etc., use only the regulations audited and approved by the Committee.