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20 December 1943

MEMORANDUM

From: OP-20-GM-F.

To: OP-20-GM.

Subject: Conference at Dayton between Mr. Desch, Lt. Comdr. R. I. Meader and Lt. L. R. Steinhardt on 18 December 1943.

1. JN-25 Additive Problem. 'There was some confusion regarding terminology of various machines for use in attack on this problem. in order to have a common basis of understanding the following definitions were agreed upon:

(a) COPPERHEAD ONE is a machine designed exclusively to locate double repeats in cipher text.

(b) COPPERHEAD TWO is a machine designed exclusively to recover additives when some additives are already known and when enough of the underlying code is recovered to select about a thousand high frequency code groups.

(c). COPPERHEAD FIVE is a new machine designed to align cipher text in depth by the application of a weighting technique such as the Hall or Shinn weights. The method of operation of this machine is to align two texts and subtract them, look up the corresponding weights and average the weights.

It will be seen from the above definitions that COPPERHEADS ONE and FIVE are designed for the purpose of aligning messages in depth, the former by means of double repeats and the latter by means of weights based on the scanning feature of the underlying code. Mr Desch and Lt. Steinhardt agreed that these two machines were of substantially equal priority at this time. COPPERHEAD TWO however, is still of relatively low priority.

The following progress on the three COPPERHEADS has been made up to this time:

(a). COPPERHEAD ONE is now in the early design stages. Mr. Desch has a very ingenious system involving punching the messages on thin aluminum foil which will circumvent the difficulties associated with the earlier porposed photographic scheme. Experiments are now being con-

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ducted on a simplified optical train and results should be known in about 10 days. Mr. Desch states that this machine will go only 1/30 as fast as the originally proposed film machine. However the present machine should be sufficiently simpler than the original proposal so that a battery of 5 units would be satisfactory. Mr. Desch states that such a 5-unit battery could run a single day's traffic against a backlog of 13 days in 24 hours. This speed figure should be considered carefully to determine if it is adequate since the design of the machine is rapidly approaching its final states. If these lower speeds are satisfactory, we may want to consider a combination of IBM and hand techniques which would yield the same speed. Mr. Desch and Lt. Steinhardt discussed one such semi-hand method and it was agreed that Lt. Steinhardt would make a formal report on the method.

(b) COPPERHEAD TWO. Because of the low priority on this project very little specific progress has been made beyond the early stages.

(c) COPPERHEAD FIVE is essentially a new project as far as N.C.M.L. is concerned and the only real progress to date is the conference between Mr. Desch and Lt. Steinhardt. As per visual instruction from GM, it was explained to Mr. Desch that the basic problem was to align two messages, subtract them, look up the corresponding weights and average the weights. The desired results are to be summarized in table showing the average of the weights versus teh relative position of the two messages. Although this is a general statement of the problem, specific details regarding the basis for and the use of Hall weights and Shinn weights, were discussed in detail. Mr. Desch plans to work on this problem during the next few days and may have some specific plans for the coming conference on 28 December 1943.

2. VIPER and PYTHON. The mechanical parts for the scramble maze of VIPERS and PYTHONS are now in production. Mr. Desch has designed a very reliable rotary switch of 30 levels, partly from standard 6-level swtiches. The first VIPER should be available for inspection on 28 December 1943. The first finished VIPER will be available during the first week of January and all of the remaining VIPERS will be finished up before the end of January. Because of the basic similarity of the two projects, the PYTHONS will come along at the same time as the VIPERS even though they may have to be placed in storage for some time until we can supply the wiring for t[ ______

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3. MIKE. Design of the counter units for MIKE is progressing nicely and no unusual problems have been encountered. The first MIKE should be ready for delivery 15 February 1944. Mr. Desch states that the nature of this device is such that it will be just as easy and quick to produce two or more MIKES as to make just one and he would like to know if GM wants more than one. The final design of MIKE is almost exactly identical to the design originally approved by GM on 5 October 1943.

4. NON-MORSE. Mr. Desch has been looking into the preliminary design requirements of the magnetic recorder for NON-MORSE transcription. The only difficulty up to the present time has been a requirement that the machine handle a total of 30 to 60 minutes recording time. Since returning from the conference GM-F has talked to Lt. Anderson and he has agreed to relieving this requirement. Lt. Anderson now prefers to have a duplex unit with provisions for switching back and forth between the two halves of the machine in a manner similar to the use of duplex projectors in motion picture projection. Each half is to be readily reloadable and the change-over will occur at either 5 or 10 minute intervals. Lt. Anderson expects one General Electric recorder before 1 January 1944 and this will be taken out to Mr. Desch for his use.

5. MONA MARK II. No changes have been made on the design of this device and it is still in the original form described in a memorandum from GM-F to GM dated 15 October 1943. Mr. Desch has the help and other facilities available for making one of these devices and he is now doing this even though GM has indicated a very low priority. Working on MONA MARK II only during spare time, delivery would be about 1 April 1944.

6. COUNTER-PRINTER UNITS. Three complete counter-printer units and three complete control cabinets are now available at N.C.M.L. Since the associated equipment from Gray Manufacturing Company is not available, the counter-printer units and control cabinets are idle. We could use these counter-printer units as general tools here in Washington and it is suggested that GM authorize shipments of one or more of these counter-printer units and control cabinets.

L. R. STEINHARDT

Lt., U.S.N.R.