• REF ID:A58755 • 

29 August 1951 

MEMORANDUM FOR AlSA-o.3 THRU AFSA-04 ~,>" 

SUBJECT: low echelon cipher machine 

l. a. Currentl.1', AFSA is developing two machines designed tor lon: 

echelon use am not requiring electrical power: .• 

(1) AFSAM-36 (The "MCM'') 

(2) DEM-17'• (The pneumatic-powered model) 

b. AFSAM--36 is a keyboard-operated "double Hagelinn device, 

with twice as Dl8IJ1' keying elements as the ~. From the standpoint ot 

pract.icabilit7 in operation (ease am rapidit7 ot setting up the machine 

to the correct d.aiq ke;y am message setting), the MCM leaves much to be 

desired. I doubt veey much whether our operators would be able to use 

the machine satisf'actoril.7. Unless special procedures are introduced 

and rii~ f'ollowed, transmissions in depth or near-depth could be 

expected, weakening the system materiall.7, or at the very least compromising the intelligence in the messages concerned. In short, in JV 

opinion the developnent along the lines ot a "double Hagelin" device 

represents our going up a blind alley. However, this development is so 

f'ar along nm that aD7 substantial changes in design would delq its 

completion beyond. a date acceptable to the NaV7 and esi)ecial.q the 

Marine Corps, the organization specif'icall.1' desirous ot ha'Vi.Dg an allmechanical crypto-machine for amphibious operations. 

c. The DEM-17 is .quite a long wq from completion but it 

represents such a novel and promising approach to the problem that, in 

JV opinion, the development should be expedited b;y all possible meam. 

2. The .moditied M-209, with irregulir stepping of key-wheels aid. 

interlocking motion, which was recentq subnitted to us by Mr. Hagelin, 

represents a marked im~t in regard to securit7 ot M-209 traffic:-

Although it remains true that two identical:q-ke;yed messages can still 

be read by our usual procedures, recovery' ot pin an::l lug settings f'or 

the day remains a problem of considerable ditticult7, it not be;yond. the 

realm of practicability with our present analytic machiner.y. Hence, 

although there would undoubtedly be occasional cases of solution, these· 

would involw onl;y two isolated messages in each instance and not the 

whole dq's traffic whenever such an instance occurs, as is now the case. 

. 3. Since the DEM-17 developnent represents an approach which 

otters promise but the. _outcane of which Will be unknown for several years, 

and since it would be inadvisable to change the design of the present 

IDl to incorporate the modified Hagelin action described in Par. 2, I 

suggest that serious consideration be given to the question as to whether 

~fENllAL 

. ·:Oe.classifi ed and approved for release by NSA on 06-16-2014 pursuantto E .o. 1352a 
SUBJECT: Low echelon • cipher machine • 29 August 1951 

AFSA should embark upon a third approach to the problem, vis., to 

develop an all-mechanical machine embodying the modified 11-209 (Hagelin) 

action in a small keyboard-operated machine. such a development would 

provide insurance against the contingency (a) that the MOM will not 

stand up und.er the test of practical war-time usage and. (b) that the 

Dl!»-17 developnent m;q also prove impractical. It appears that at 

least the NaV7 (Marine Corps) needs something better than the present 

M-209. Although neither the Ar'fJIT nor the Air Force has thus tar submitted. MC•s tor such a piece ot equipnent as the Mell, I believe that 

there is a need (which is currently being met by the present M-209) and 

that, as regards the ArlllT, the need ma:y becane very urgent in the near ~ture. · · . 

4. Although the patent situation is not clear with regard to U.S. 

ownership of a license to the Hagelin improvement under discussion, I 

do not think there would be &JV' difficulty in reaching a satisfactory 

understanding with Mr. Hagelin, in case we should wish to use the· 

principles umerlying the improvement. 

5. AFSA still has the experimental model or the modified U-209 

sent by Ml-. Hagel1n last December and I promised recentq to return it 

to him ver7 soon. However, in view of this memorandum I will keep the 

model a few dap longer, pending a determination as to whether it would 

be useful to retain it for purposes of discussing m:y suggestion. 

6. Your comments are requested. on the suggestion made in Par. 3; 

and in view ot Par. 5, they should be forwarded as promptly' as possible, 

so that I ma:y know· soon whether to ask Mr. Hagelin tor an ext.ension ot 

the loan ot the model. 

Into. Cow to: 

AFSA-00 ) 

AFSA-OOA ) in turn 

AFSA-OOB ) 

AFSA-OOC ) 

AF~OOT