More information on Office of Strategic Services and Office of War Information cryptosystems

In my essays Compromise of OWI - Office of War Information communications and Allen Dulles and the compromise of OSS codes in WWII i’ve looked into the compromise of OSS and OWI communications in WWII. Unfortunately it is very difficult to find detailed information on the cryptosystems used by these organizations in WWII but a report found in SRH-145 ‘Collection of memoranda on operations of SIS intercept activities and dissemination 1942-45’, dated 16 October 1943 says that they used cipher machines and hand systems (M-138 strip cipher and double transposition).

I’ve added this information in the aforementioned essays.

Acknowledgements: I have to thank Rene Stein of the National Cryptologic Museum for sending me SRH-145.