(SIGTOT)cryptographicsystem for c~ssfiied message traffic between Atomic Mergy Commission activities in the United States and the fop ward area. This decisionwas based on the fact that Atomic Energy Comssion approved of and had been using SIGTOT; consequently,trained Personnel and the necessary equipmentwere already available. SIGTOT kko protides one of the most secure means of transmittingclassified information. Through conferenceswith Commandeer. J. Schmidt of the c~cations Section, Commander James Hargraves, Lieutenant J. M. Jonee and Mr. John Kelly of the Department of the Navy, it was decided that three (3) SIGTOT equipmentswould be required on each AV and five (5) SIGTOT equipments on the AGC-7. This would provide the necess~ coding facilities for a three-way SIGTOT conference. One SIGTOT would be used to transmit to the other two ships and ~ne SIGTOT ueed td receive from each of the other ships. The two remining equipments on the AGC-7 could simultaneouslybe used to encode and decode other messages while the conferencewas in progress. 0n7 November 1947 it was decided that all Atomic Mergy Cmmission traffic to and from the ships would pass through Los Alamos, This would reduce the number of tape systems held by the ships to a minimum since all messages from Atomic Ehergy Camdssion activities in the United States addressed to the ships would be sent to Los Alsmos by existing consnercislTWX circuits where the messages would be decoded and re-encoded in the system held jointlyby Los Alamos and the addressees -* chip. The SIGTOT tapee required for message handling and teletype conference were requested on 2Q Nowmber1947. below: 1 41 Section XI This request is summarized