Major Update of the U.S. KL-7 Simulator

KL-7 Sim Version 5.0

It's been more than three years now since I  released my TSEC/KL-7 simulator. Today, this crypto machine simulation is definitely my favorite. Not in the least because I had to start from scratch, both historically and technically, when I decided to develop this KL-7 sim.

Last year, Uri Blumenthal from MIT proposed to develop a JAVA version of my KL-7 simulator. His version was  finished and published three months ago. However, since 2011, new information had been declassified, making an even more accurate simulation possible and providing new information to add to the historical sections of the sim's manual.

If it wasn't for Uri, I had never embarked on this new and sleep-depriving project to update the KL-7 sim. He wanted to adapt his JAVA version according to the latest info and insisted not only that I updated my simulation, but also to make both sims fully interoperable. Of course, cryptographically, both sims were already compatible, but they now have the same key file format, they offer similar software nuts and bolts and the encryption procedures are on par.

We now both published our version 5.0, which is as complete and accurate as it can get. Here's a list of changes, applied on version 5.0 of the KL-7 Simulator:

• Renaming of rotor assembly parts and other components according to the real KL-7 manual
• Notch rings now set relative to the alphabet ring by letters, instead of against the core by numbers
• Added a 13th rotor, introduced in 1975
• All rotor cores interchangeable, also for the fourth rotor, which has to be equipped with a special "wide ring"
• Re-wrote  the encryption procedures according to the declassified KAO-41C/TSEC, corrected key sheet examples and revised the technical and historical sections of the manual.
• Saving and opening of key files in .txt file format *
• Set Mode for quick and easy adjusting of the rotor alignment (start position of the rotors) *
• A software zeroize button *
• Switching between letters and figures with either arrows Up and Down or the SHIFT *

* Not available on the real KL-7 machine.

The KL-7 simulator is an historical reference to a magnificent crypto machine and it's fun to use! The 20 page manual shows how to work with the simulator, how to encrypt messages, exciting example training messages straight from the Cuban missile crisis, the technical details, history on the development and use of the machine and, as such a notorious machine deserves, fascinating spy stories involving the KL-7.

My first acquaintance with the KL-7 was years ago, on the battleship HMS Belfast in London, where it was displayed behind glass. For decades, this Cold War cryptologic beauty, developed by ASA and AFSA, and introduced by NSA in 1953, remained hidden under a veil of secrecy and there were no historical, scientific or technical publications whatsoever to start from. It's been quite an interesting journey before arriving at today's new version.

The project was one of evolution and a few updates, since we always strive to provide the most accurate historical and technical information. That's what makes the difference between a toy and a truthful simulation. The previous version, published in March 2011, finally worked as it should, at least when it came to machine output and graphics.

However, some details, names and procedures were still unknown. Also, the KL-7 sim's nuts and bolts were operated in exactly the same way as the real machine, and that's not really the impatient software user's cup of tea. A returning question was why it is so elaborate to work with these crypto simulations. Of course, the reason is that the software works exactly like the real thing. Otherwise, it wasn't a simulation. Version 5.0 meets those requests and has some extra features the KL7 that operators back then would have loved on their machine.

The KL-7 simulator for Windows and JAVA KL-7 are available for download on Cipher Machines and Cryptology and since history is there to share, it's freeware, as usual. Please read the readme.txt file in the download Zip before installing the software. Any previous version should be uninstalled first via the Windows Configuration Screen.

The Military Liaison Mission

SOXMIS Vehicle Report Card

After World War II, British, American, Soviet and later the French allies agreed to accredit military liaison missions near the headquarters of each other's occupation zones in Germany. On November 14, 1944, the first directives were written down in the London agreement of what later became an important tool to limit tensions during the Cold War.

The first Military Liaison Mission (MLM) was established in September 1946 by the British and Soviet forces. The British Mission (BRIXMIS) was located in Potsdam, within the Soviet occupation zone which would later become the German Democratic Republic, commonly known as East Germany. Their Soviet Military Mission counterpart (SMM BAOR),  also known as SOXMIS, was consecutively located in Bad Salzuflen, Lübbecke and in Bünde, all inside the British Army of the Rhine (BAOR) occupation zone in West Germany.

The U.S. and Soviet forces signed an agreement in March 1947. The U.S. Military Liaison Mission (USMLM) was also housed in Potsdam. Their Soviet Military Mission counterpart in the U.S. Army Europe occupation zone (SSM USAEUR) had its offices in Frankfurt am Main.

The French and Soviet missions were established in April 1947, with the Mission Militaire Francaise de Liaison (MMFL) building in Potsdam and the Mission Militaire Sovietique (MMS CCFA) in the French occupation zone, Commandant en Chef Français en Allemagne (CCFA) in Baden-Baden.

 

Keeping the Cold War Cold

The military liaison missions continued throughout the Cold War until 1990. Initially implemented for economical monitoring and a communications channel between the different allied powers in occupied Germany, the liaison's mission gradually changed into a military intelligence mission when tension rose between the West and the Soviet Union. To relief the Cold War tensions, the MLM's were used more and more to verify the build-up, movement of troops and their equipment in East and West Germany. This enabled them to see whether bilateral agreements regarding troops and equipment were respected.

No spooks allowed!

Although having a quasi-diplomatic status - it was not allowed to stop their vehicles - they were forbidden to travel within certain, mostly military, restricted areas. They were always in uniform, drove official military vehicles with very recognizable license plates and never carried weapons or radio equipment. Needless to say, the MLM's were not allowed to mount real intelligence operations. They never operated covertly but did get involved in clandestine actions.

Monitoring and Spying

Of course, to get the most interesting military intelligence, the rules had to be bent once in a while, in order to get the perfect photo of some new tank or aircraft. However, caution had to be taken to avoid creating tensions or jeopardize the MLM agreements. Nonetheless, several severe incidents occurred, even with fatalities, like USMLM Major Arthur Nicholson who was shot by a Russian guard at a Soviet tank storage building near Ludwigslust in East Germany.

USMLM Car in East German forest
Image: ColdWarSpies

While stationed in Germany, we were ordered to immediately report any SOXMIS vehicle we saw. Undoubtedly, the same was done on Soviets side, and although the MLM vehicles were officially never stopped, they sometimes "accidentally" got hit or were "unintentionally" pushed off the road. Although tensions could rise quickly in case of incidents, neither side was eager to blow up the liaison agreements as doing so would also deprive themselves from the opportunity to gather intelligence in the occupation zones of their Cold War enemy.

Despite the cat and mouse games on both sides, the Military Liaison Missions were an important contribution to the stabilization of tensions during the Cold War, especially because they showed that the adversary was not gathering large offensive forces in East and West Germany, the Cold War frontier of Europe.

On ColdWarSpies.com you find a detailed history section (1964 - 1988) of the U.S. Military Liaison Missions. The site also contains several audio interviews with former USMLM members and a large photo archive. The older USMLM.US website is available at the Internet Archive. You also can visit the BRIXMIS Association, the MMFL Veterans) (in French, archived) and Unsichtbar Unterwegs in der DDR, a nice article on the challenges the MLM drivers faced during their missions (in German).

Firsthand Accounts

 

Cold War Conversations has a podcast interview with Major Nigel Dunkley who served in Berlin with a tank squadron, defending the British sector of Berlin and he gathered intelligence for BRIXMIS in the Soviet occupation zone in East Germany. A fascinating 90 minutes interview

At the Spy Museum Podcast there are also two fascinating podcasts, one with Brigadier General Roland Lajoie in 2011 and one with Major General Michael Ennis last April. They both served in the USMLM. The Livedrop interviewed Stephen Hoyt, former analyst and president of the USMLM Association.

The excellent 45 minutes documentary Meet The Real Cold War Spies Of BRIXMIS, with former members of the Military Liaison Mission.

Meet The Real Cold War Spies Of BRIXMIS

The Cold War Pioneers talk by Stephen Hoyt at the U.S. Army Heritage and Education Center (USAHEC).

Cold War Pioneers: The U.S. Military Liasion Mission, 1947 - 1990

Cold War Documentary

Cold War is an excellent and most comprehensive documentary series about the Cold War. From the roots of the Cold War to the fall of the Berlin Wall.

It's all explained in detail in twenty-four 45 minutes episodes, that's no less than 18 hours. The numerous interviews with the main characters of the Cold War are most interesting. More information is found at the Internet Movie Data Base

Cold War - Comrades [E1/24]