Update

In Compromise of State Department communications in WWII I made the following correction. I had written that the M-325 SIGFOY cipher machine was introduced into service in the second half of 1944, however that was not correct.

According to NARA - RG 59 - Purport Lists for the Department of State Decimal File 1910-1944 – microfilm 611 - 119.25 MC-325 the device was distributed to foreign posts in the second half of 1944 but the keylists were for the period January-June 1945. Thus the device could not have been used in 1944 by the State Department.