Joint Chiefs of Staff evaluation of Office of Strategic Services ciphers

In 1943 and 1944 the US Joint Chiefs of Staff evaluated the cryptosystems used by the various US government agencies.

For example the report on State Department codes and ciphers for 1943 can be found in the NSA website and the report of 1944 is in the US national archives, in collection RG 457- Entry 9032- box 1384 - 'JCS Ad hoc committee report on cryptographic security of government communications'.

The ciphers of the Office of Strategic Services were also evaluated and there is some information on this topic in the US national archives, specifically Record Group 226 - Series: Correspondence Files, 1942 – 1946 - File Unit: 17) Cryptographic Security:

Unfortunately there are no detailed reports on the subject but from the information presented above it seems that even as late as 1944 OSS communications were sent on vulnerable cryptosystems (double transposition and M-138-A cipher).