Monday, September 10, 2018

German solution of State Department A-1 Code in 1944

During WWII the US State Department used several codebooks for enciphering radio telegrams. These were the low level Gray and Brown codes and the high level A1, B1 and C1 codes.

The latter codebooks were used with substitution tables.

It is clear that the German codebreakers were able to solve the substitution tables used with the A1 and C1 codes till late 1943 because these were given to the Japanese and decoded by the Allies in late 1944 (1):

According to a message of the Japanese military attaché the C1 code continued to be used by the US embassy in Bern, Switzerland so those messages could be read in 1944 (2):

Were the Germans also able to read messages enciphered on the A1 codebook in 1944?

The book ‘Hitler, the Allies, and the Jews’ by Shlomo Aronson mentions a message solved by the codebreakers of OKW/Chi (German High Command’s deciphering department) (3):

At the same time, the OKW/Chi decrypts tell us in their way what the Allies were doing in various ways, including the hectic activities of WRB's operatives upon its inception. Thus, the following cable from Washington, dated February 9, 1944, from the State Department and signed by Secretary of State Cordell Hull but in fact sent by the WRB to the American Legation in Bern, dealt with funds made available to the International Red Cross (ICRC) in Geneva to help Jews in Rumania, Croatia, Hungary, Slovakia, and Theresienstadt by the Joint Distribution Committee (AJDC), as authorized by the Treasury Department’.

The original message can be found in the US National Archives (4) and the classification is SECRET.

The note on the first page says A-1 so I assume that it was sent using the A-1 codebook. 

Thus it seems that the Germans continued to read diplomatic traffic sent on the A-1 code even in 1944.


(1). US National Archives - collection RG 457 - Entry 9032 - box 1.018 - NR3225 ‘JAT write up - selections from JMA traffic'

(2). UK National archives HW 40/132 ‘Decrypts relating to enemy exploitation of US State Department cyphers, with related correspondence’.

(4). US National Archives - Microfilm Publication M1284, roll 38, indexed to file ‘840.48 Refugees/5195’. 

Saturday, September 8, 2018

Remaining research projects

What files am I still trying to locate? Let’s see.

1). TICOM report I-40

I requested this file from the NSA FOIA office in 2015. It was quickly located and placed in the review queue. However it has not been declassified yet…

2).  NAAS 5 reports:

There are two German Army signal intelligence reports covering the work of the NAAS 5 unit for the second half of 1944:

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

According to the NSA FOIA office they are probably in transfer group TR-0457-2017-0010. 

These files have been sent to the US National archives so I have to wait for NARA to process these files and then I can ask them to locate the NAAS 5 reports (assuming they are really there…).

3). Henriksson report:

According to my information on 18 October 1944 there was a meeting in Sweden between the US officials Wilho Tikander and L. Randolph Higgs and the Finnish officials Reino Hallamaa and Karl-Erik Henriksson.

Henriksson was the Finnish expert on US codes and ciphers and in this meeting he gave the Americans detailed information on the compromise of their diplomatic communications.

My researcher and the NARA research department have checked the files in collection RG 84 ‘Records of the Foreign Service Posts of the Department of State’ - ‘US Legation/Embassy Stockholm, Sweden’ - ‘Top Secret General Records File: 1944’ but they could not locate this file.

Thus I have filed FOIA requests with NARA and the State Department regarding this file. Maybe I’ll get lucky.