A US Navy WWII Encryption Device

[Puster Bill]

Originally Posted by CDR Resser

Kim Ronhof over at subsowespac.com, and the Pacific Thunder site built an electronic cipher program for communications within the Pacific Thunder Campaign. He might have some of the information that you are looking for. Sorry, I don't know his email address.

Respectfully Submitted;
CDR Resser

Thanks. I took a look at what they had at subsowespac.org, and it appears to be an electronic version of the SIGABA/CSP-888/889 cipher machine. The CSP-888/889 was a rotor machine, essentially a more complicated version of the German Enigma.

If I were going to use a simulation of a CSP-888/889, I'd probably use the one found at Frode Weierud's 'CryptoCellar':
http://cryptocellar.org/simula/sigaba/

The Navy also used the M-209, which they designated as CSP-1500. Dirk Rijmenants (of Enigma Simulator fame) has a nifty M-209 simulator here:
http://users.telenet.be/d.rijmenants/en/m209sim.htm

The CSP-1500 was actually the replacement for the CSP-488 that I implemented here. It was somewhat more secure, but could still be broken if enough plaintext could be had, or if two or more messages had keys that overlapped. Apparently, it was used to communicate with units that didn't have the (presumably more secure) CSP-845 strip cipher.

I have neither the time, the skills, nor the money to build a SIGABA or an M-209, though. Nor do I have the money to buy them (M-209's occasionally come up for sale). I do have the time and patience to make strip ciphers, though.

By the way, I re-did the CSP-488 Mk II into a vertical orientation, and I used my wife's paper cutter to cut out the strips, which made it *SO* much easier. I'll post a pic when I get a chance. I now have an EXCEL file for the strips, and a Word document for the strip holder.

[Puster Bill]

OK, here is the new and improved vertically oriented CSP-488 Mk II:



I may improve on it yet again. My thinking is that I should cover the center of the strip holder, between the two retention strips on either side, with an inkjet transparency that has a number of vertical lines down it, to correspond the columns generated by the strips, and perhaps to designate them with a letter or a number to make it easier to read the columns.

Either that, or I may just run a piece of thread down the center for alignment purposes.

[Puster Bill]

MSG 213 Z 210255Z AUG 42 GR22
bt
YDVEV BJGWZ ROUJQ ISVZA PTIDC PBBJG OWIAB ZGQEM BJWMI SJRMT
OQSDH OZXSS EUNVR NHYSV SOXPA IOYPR JQBXV DKULG OVZNW JIVTX
YXDYN VVMCT
ar K

[Puster Bill]

OK, I'm going to ask for some help from anyone near Pensacola Florida.

The US Navy used a strip cipher during WWII called the "CSP-642". I was a lower-level cipher similar to the ones I posted above, except that there were 30 strips, and they used 25 to 30 of them at a time, depending on the particular key for that day.

The Japanese captured examples of it at Wake and the Aleutians, but even though they devoted considerable effort in breaking it, they only had spotty success. They recognized that it was used by US subs, though, by the indicators used: BIMEC and FEMYH.

I have been unable to find any images of it online.

There is an example of this cipher at the Naval Security Group Command at Corry Station. It's called the "Wenger Command Display". It's open to the public, the information necessary to visit personally is here:
http://ehistory.osu.edu/wwii/interac...nger/index.cfm

If anyone can get me some good, clear pictures of it, I can make up the files necessary and then upload them.

I *COULD* make a notional example with my own mixed alphabet strips, but I'd rather it be based on the real thing if possible.

Thanks in advance.

[Puster Bill]

OK, I got good photocopies of an original CSP-642 US Navy strip cipher. When I get the chance, I'll make both a detailed copy, and an easy to build analogue, and I will post the images and instructions here.

[Hitman]

In case it's a different one, here's also one offered by the guys at Subsowespac: http://www.subsowespac.org/silent_hunter_mods.shtml#21