CX-52/C-52 by Crypto AG

The CX-52 was originally produced in a rotor vesion followed  by a random paper tape (RT) reader version (CX52RT 200Type32) Both were made in Sweden by AB Cryptotenik, Sweden for Crypto AG in Zug, Switzerland.

So what is  the basic difference between the Hagelin C-52 and CX-52?  - It's the way the pin wheels step. On the C-52 model, the stepping is somewhat similar to the one on the C-38 (M-209). On the CX model, the stepping depends on settings of the pins and the lugs on the drum. They also have different wheels, where the C-52 has a selectable set of 12 different pinwheels (more or less co-primes) and the CX has normally 6 identical pinwheels. Nonetheless, there are many customized versions of the C(X)52.

Cranking the side lever operates the machine but an additional keyboard unit, motorized this action thus increasing the throughput of the machine. The lubricating plan can be seen on the top face of the keyboard unit.  Please note the image with the red border is only to show the machine with its matching keyboard unit, the B52. When the CX-52 machine is used with the B52 keyboard it's known as the BC52.

Ralph Simpson comments on the C-52.

"All the articles on the internet that say the C-52 has "irregular" wheel movements are incorrect. Most say that the CX-52 has more irregular wheel movement. What all these article share is a lack of details about exactly what is different between these devices. The truth is that the C-52 has regular and fixed wheel movements!

There are many different versions of these devices, but the CX-52 has lugs on the wheel movement bars which gives irregular wheel movements which is settable by a daily key. The C-52 has 5 wheel movement bars with fixed teeth, so there is no chance to set a different daily key. Lugs do not work on these bars.

In fact, my C-52 has 3 of the 5 bars disabled! The other two wheel movement bars move wheels 1 and 2 one position and the last 4 wheels 2 positions for every letter entered. Period. No changes allowed, unless you go through the effort of replacing the bars. But my drum will still disable 3 of the bars, so wheel movements will be limited to only 2 bars.

So the movement is not one position for each key entered, like the earlier devices, but as regular as can be. Various models of the C-52 may have other wheel movements, but these wheel movements may have been shared with the NSA or if the NSA had to break it, they only needed to do that once. So wheel movement added zero cryptologic strength to the C-52! This was step one in the Gentlemen's Agreement. Step two was writing the user's manual to limit the variability of the lugs and pins".

A B621 keyboard assembly - front view. (E-bay photo)
End view. (E-bay photo)
Rear view. (E-bay photo)
This is the copy which accompanied the B-621 keyboard while it was on sale on E-bay.

"An AC/DC electric drive unit with keyboard for use with the Hagelin C52 cipher machine which provided the ability for the mechanical machine  (C52/CX52) to be used at speed and  also for use with larger, purpose built crypto off-line equipment. Nothing else known about this device"

This variant of the CX52, complete with carrying case and accessories, is fitted with a keyboard and letter ring which only has 10 characters - number 0 through 9.

To change a pin wheel machine to a RT ( Random Tape) machine, the 6 wheel rotors were replaced  by the tape reader. A different metal cover place would also have to be installed.
Various views of the CX-52, Type 32 paper tape reader version . Its weight is 3 kg. (Photos courtesy E-bay) 

A Cold War era CX-52 with the letter ring and typewheel in Farsi so it may have been in use in Iran during its heyday. 

This model is capable of operating in an ‘incremental mode’ whereby plaintext and ciphertext alphabets separate. The plaintext alphabet prints its character and then remains still, the ciphertext alphabet cycles, prints one cypher character and then reconnects to the plaintext alphabet, in a new position, before the next character is entered. 

Sounds complicated? Well, it basically means that the final cyphertext is harder to break as each cyphertext character depends upon all previous text entered. Its easier to see and understand than it is to explain it!

In non-incremental mode, the typewheel plaintext and printing alphabets maintain constant positions relative to one another. (Photos and copy courtesy John Alexander, G7GCK Leicester, England. E-mail: See Museum Info section).

B621A electric keyboard. It has AC/DC electric drive unit  for use with the Hagelin C52/CX52 cipher machines and includes something at the left side which the BC621 lacks . It can also be used with larger, purpose built crypto off-line equipment.

The design of the C52/CX-52 is such that it can be transformed into an electrically driven keyboard operated machine by the addition of an electric drive unit, designated the BC-621A, which comprises of a  keyboard, setting and driving mechanism. When an electrically operated machine is required, a C52/CX-52 machine is slid onto the B-621A base and locked into place. Dimensions: 12 1/2" x 8 1/2" x 6 3/8"   (Photo via E-bay)

This CX-52 was used by the Spanish Air Force and by 1994 it became an  exhibit at the  Talavera la Real AB Museum in Spain. The streaks in the photo were produced by the plexiglass case protecting the artifact. (Photo by Gorka Luis Martinez Mezo) 
CX-52 pin setting tool. (Photos via E-bay)
Mark Sims offers his advice for CX52 ink rollers. "Another useful bit of info for M-209/CX-52/C-446/BC-543 users is a good source of ink rollers for the machines.  Most office supply stores carry the NuKote NR-40P ink roller for calculators.  It is also numbered EA770R,  CP-16, or IR-40 by other manufacturers.  It is used by over 100 different  calculators.

The ink element is the exact inside and outside diameter as the M209/CX52/BC543 ink roller,  but about 1/8" longer.  It is very easy to modify the calculator roller for use with the cipher machines.  Wear gloves,   it's incredibly messy and the roller gushes ink at the slightest provocation.

First snap the roller/axle out of the "U" shaped clip.  Next take the roller off of the axle.  I have found it easiest and cleanest to cut the end of the  axle off first.  I use a pair of diagonal wire cutters.   Next trim the roller with a razor blade or surgical scissors to 3/8" long.   I have found it easiest to get a clean square cut with the surgical scissors.   Finally the roller needs the small brass axle from a real roller or you can cut one off of a piece of 3/32" O.D. brass tubing from a hobby shop".

Mark Sims <holrum(at)>

For more on the C-52 and CX-52 please refer to the web site of Dirk Rijmenants.

Contributors and Credits:

1) Dirk Rijmenants <DR.Defcom(at)>
2) Frode Weierud <Frode.Weierud(at)>
3) Klaus Kopacz <ibk_mail(at)>
4) Ralph Simpson  ralphenator(at)>
5) Gorka Luis Martinez Mezo [glmm2001(at)]

 Back To Menu Page

July 26/23