the US State Department used several cryptosystems in order to protect its
radio communications from the Axis powers. For low level messages the
unenciphered Gray and Brown codebooks were used. For important
messages four different codebooks (A1,B1,C1,D1) enciphered with substitution
tables were available.
Finns and Japanese cooperated on the solution of the strip cipher. The Japanese
gave to the Germans alphabet strips and numerical keys that they had copied
from a US consulate and these were passed on by the Germans to their Finnish
allies. Then in 1943 the Finns started sharing their results with Japan.
the information we have today on the compromise
of the State Department’s strips cipher is limited. One problem is that the
archives of the agencies that worked on this system are not available to
researchers. Three different German agencies worked on the US
diplomatic M-138-A strip cipher. The German High Command’s deciphering
department – OKW/Chi, the
Foreign Ministry’s deciphering deparment Pers Z and the Air Ministry’s Research Department - Reichsluftfahrtministerium Forschungsamt.
I know that
the NSA has some interesting reports on the codebreaking successes of the Forschungsamt but they have not been declassified
yet. Regarding OKW/Chi I don’t know if their archives (or parts of them)
survived the war. Finally the files of the Pers Z agency were captured by the
Anglo-Americans at the end of the war but the reports I’ve seen from the National
Archives and Records Administration are mostly administrative files.
This means that so far our sources on the strip compromise are mainly
TICOM reports written postwar.
Finnish codebreakers and the strip cipher
codebreakers also worked on the strip cipher and solved several links in
the period 1942-44. In this area there was cooperation with their German
counterparts, not only in receiving copies of the Japanese cipher material but
also exchanges of personnel and analysis of the strip system.
The fact that
the Finns cooperated with the Germans against this cryptosystem means that we
can find out more about the German operation through Finnish sources and thus
circumvent the lack of German archival sources.
1944 Finland signed an armistice with the Soviet Union. The people in charge of
the Finnish signal intelligence service anticipated this move and fearing a
Soviet takeover of the country had taken measures to relocate the radio service
to Sweden. This operation was called Stella Polaris (Polar Star).
September roughly 700 people, comprising members of the intelligence services
and their families were transported by ship to Sweden. The Finns had come to an
agreement with the Swedish intelligence service that their people would be
allowed to stay and in return the Swedes would get the Finnish crypto archives
and their radio equipment. At the same time colonel Hallamaa, head of the
signals intelligence service, gathered funds for the Stella Polaris group by
selling the solved codes in the Finnish archives to the Americans, British and
Japanese. The Stella Polaris operation was dependent on secrecy. However the
open market for Soviet codes made the Swedish government uneasy. In the end
most of the Finnish personnel chose to return to Finland, since the feared
Soviet takeover did not materialize.
American reaction and the Carlson-Goldsberry report
the NSA study History
of Venona (Ft. George G. Meade: Center for Cryptologic
History, 1995) by Robert Louis Benson and Cecil J. Phillips, it was at that
time that the Finns revealed to the US authorities that they had solved their
diplomatic codes. On 29 September 1944 colonel Hallamaa met with L.Randolph
Higgs of the US embassy in Stockholm and told him about their success.
In response two
cryptanalysts were sent from the US to evaluate the compromise of US codes in
more detail. They were Paavo Carlson of the Army’s Signal Security Agency-SSA
and Paul E. Goldsberry of the State
Department’s cipher unit. Their report dated 23 November 1944 had details
on the solution of US systems.
finding this report has proven to be quite a problem!
Freedom of Information Act requests
to find this report in the US archives i gave up and filed FOIA requests with
the State Department, NSA and NARA. The results:
1). The State Department told me that they no
longer have these files as they have been sent to NARA so I should bother them.
could not locate this file but they did send me a list of references that I
should look up.
3). The NSA informed
me that they had expended the free time allowed for research and if I wanted to
continue I’d have to pay. I decided not to.
the FOIA requests I tried to find information on the people responsible for
evaluating the compromise of State Department codes during the war. A name that came up in relevant reports was
Assistant Secretary Shaw. This was Gardiner Howland Shaw, Assistant Secretary of State in the period
1941-44 and in charge of the State Department’s cipher unit.
Unfortunately NARA does not have a separate body of records for G. Howland
I followed was the Shaw foundation
but their response was that ‘To our
knowledge, he left no immediate family members and we have no record of any of
his State Dept work.’
messages from the embassy in Sweden
to find anything either with the FOIA requests or the Shaw search I decided it
would be best to try to track down the messages sent from the US embassy Sweden
to Washington during the days mentoned in ‘History of Venona’. Unfortunately the State Department messages are
indexed according to a complicated system and it is very difficult to find
So I asked NARA again if they could locate the
messages of the embassy in Sweden for these specific dates and their response
searched the Source Cards, 1940-1944; General Records of the Department of
State, Record Group 59 and located index cards which lead us to believe that no
record of these sensitive meetings/topics were kept by the State Department.
It is possible, though, that further examination of this series may yield
records which may be pertinent to your research.’
They also gave me a reference to an OSS report in the Director’s files
but I had already checked that.
Now I have to give credit where credit is due and the NARA people
really did some great work in this case! Unfortunately even after all these
efforts the Carlson-Goldsberry
report continues to elude us…
haven’t been able to find the actual report I think that a page found in NARA-RG
457-Entry 9032-box 214-‘M-138-A numerical keys/daily key table/alphabet
strips’ is a part of that report or at least contains information from it.
As can be
seen in that page it says Department of State- Assistant Secretary, which
should be G. Howland Shaw and the date says 23/11/1944, which matches the ‘History of Venona’ date. The file shows the
coupling of alphabet strips with a set of keylists. This implies that the State
Department did not use separate sets for each embassy but instead had a limited number of strips and
keylists that were rearranged during the war.
March 2018: The NSA
FOIA/MDR office has declassified this report. (Google