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AKTIEBOLA.GET CBYPTOTBKXIK 

STOCKHOLM 30 

REF ID:A58956 

OCOP 3ECRElJ 

Sundsvik, August 9, 1950. 

,!. -

OIREKTIONEN 

Dear Bills 

You have surely realized long ago that my "career" as a designer of 

ciphering devices has been rather spotty. I have taken my work more 

or less as a hobby, and I have not bothered too much about theory On the other hand, it is a rather special field, and to combine a• r '' 

full. knowledge~ of the art of ciphering and of decrypting, with a )· 1 

flair.for design, ls not always possible. · ; 

This may explain - to some extent, at least - why ther~ haue been/ : 

no proof or my activities for quite a long time, although :t: have )>ea: talking about new inventions for aev~ral years. : 

----- he«. : From my memo of Aug.5 you will have found that we now at least two 

" 

new machines past the talking stages the so calle6 "cryptex" and a 

new mechanical machine (which I hope may supersede the M-209). Both machines are based on my new displacing mechanism, of which 

you will get a description at an early date. 

When d~signing the ''Crypt ex" I had several alternatives in mind. 

'l'hey wares 

l/ An auxiliary machine, like the Cryptex. 2/ An electric ciphering ma.ine. 

3/ A combination electric ciphering machine -

For these machines I wanted to use (depending preference) following ciphering mechanismss 

a/ A mechanism, producing an inversion cipher, 

ciphering telewr1ter.: 1 

on the customer's. / l 

, :I 

b/ A mechanism, producing a double substitution cipher, 

c/ A mechanism, producing a combined inversion-double substitution 

cipher. 

1 

All the above combinations and alternatives have been worked out · .:, .... ~ , on paper, and I know how I want to build the different machines •. ~ ; 

There will be standardized parts to a considerable extent,,f.i. 1 

the displacing mechanism will be the same for all machines, also the' 

sending- and receiving equipment for 1/ & 3/,J(the keyboard and the · 

printing mechani em for 2/ & 3/ • las per IIlY memo of ~ 5/ •

1 At present we are working on the pr,ototypes tor the machine la/~. . and I am working on the designs for the other ty?es. The most dlff1~l 

cult part 1s the printing mechanism, where we will use an old idea' 1 in a nov~l way. . ~ . : ,

1 

With regard to the double substitution cipher machines, I am ~sing -'l 

there 4 ciphering cylinders, which are displaced with ~he a1d~ot the 

new displacing meqhaelsm. The cylinders will have very small dimen'e~ 

sions, and all the conneclions can be changed without removing the ~ 

cylinders from the machine. , A~ 

As to weights and dimensions, the following figures are ~~~.Jllmrox~ mative, and I hope that we can do better, when we have tliiaiil'gns. 'i 

completed. .~ 1 

N$0 1/ l! x 10 x 61", 40 lbs. ·}, \

1

1 

N'so 2/ l r 12-lx 6 11 , 50 lbs. · '. , N~o 3/ 1 x 14 x 6 , 60 lbs. ~ : 

----Very best reaards, from ''', · ,":, 1 

c Sincerely yours · · · 

'"-

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Declassified and approved for release by NSA on 07-14-2014 pursuantto E.O. 1352a