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Tempest Proof Docking Stations

As wireless technology in law enforcement becomes more critical, so is the importance of protecting that technology and the information gathered. The public safety goal to protect and to serve isn’t just limited to the streets. It must also include our technology infrastructure.

We rely heavily on the intelligence gathered in the Records Management Systems (RMS). These systems are constantly at risk of threats beyond the walls of their physical jurisdiction and encompass the ubiquitous unknown of the cyber world. The necessity of these RMS databases is rarely contested. A more pressing question is how to protect them. Factoring in the many essential mobile workstations in patrol vehicles as well as laptop units that can’t be kept behind constant lock and key, how can management protect data without limiting efficiency?

Markus Kuhn, a well-known German scientist and expert in computer security, focused his primary research on computer security, in particular the hardware and signal-processing aspects of it. Kuhn found several low-cost software techniques for reducing the chances that emanations from computer displays can be monitored remotely.

With CRT displays and analog video cables, filtering out high-frequency components from fonts before rendering them on a computer screen will attenuate the energy at which text characters are broadcast. With modern flat-panel displays, the high-speed, serial digital interface (SDI) or digital visual interface (DVI) cables from the graphics controller are a main source of compromising emanations.

LED indicators on computer equipment can be a source of compromising optical emanations. One such technique involves the monitoring of the lights on a network switch. Almost all network switches flash to show activity, and it is normal for the flashes to be directly taken from the data line. As such, a fast optical system can easily see the changes in the flickers from the data being transmitted down the wire. From here, it is a time-consuming path to recover the data, but a computer, once correctly programmed, can reveal the data packets and text in real time.

Recent research has shown it is possible to detect the radiation corresponding to a key press event from not only wireless (radio) keyboards, but also from traditional wired keyboards and from laptop keyboards. Many law enforcement agencies are using Bluetooth keyboards or Bluetooth accessories in their mobile computing solutions. The average street criminal isn’t going have the ability to intercept anything, but if anyone in law enforcement thinks organized crime isn’t aware or capable of interception, they are naïve.

In recent years, a federal mandate forced Canadian law enforcement agencies to strengthen network and access security to its main federal database which holds the nation’s criminal records. The new standard of security forced the Canadian agencies to revamp their information security, including implementing a new user authentication process. Canada’s strong identification and authentication (I&A) requirements mean agencies have to find a way to be sure the individuals accessing the network are in fact who they say they are and that they are cleared to enter network areas.
Now front line officers must insert a thumbdrive-like device, called an EToken. This eliminates the need for network user names and passwords, which was an element of the Royal Canadian Mounted Police mandate that Canadian law enforcement agencies must comply with. ETokens provide two-factor authentication (2FA), password and digital identity management, which essentially is “something you have, and something you know.”

Law enforcement Information Technology directors are mindful and diligent about safeguarding sensitive data. But it’s not only the moral code of IT managers that dictates that sensitive, valuable data is protected. Since 2003, when California passed a historic data breach law, many states have followed suit, enacting similar laws to protect consumers’ rights and personal data privacy.

So if law enforcement has taken steps to stop system intrusions from criminals directly logging into its systems, the next best way to get that information would be to simply intercept it as its flying around the wireless networks—perhaps between the police vehicles laptop modem and the commercial cellular data network. Many would say, “But you can’t intercept it because it’s encrypted by both the carrier and the agency’s software.” Well, the U.S. and Canadian military has been concerned about this for years. They commonly refer to it as “Tempesting.” This may now be something that law enforcement needs to consider.

TEMPEST is a code name referring to investigations and studies of compromising emanations. Compromising emanations are defined as unintentional intelligence-bearing signals which, if intercepted and analyzed, may disclose the information transmitted, received, handled, or otherwise processed by any information-processing equipment.

Compromising emanations consist of electrical, mechanical or acoustical energy intentionally or, by mishap, unintentionally emitted by any number of sources within equipment/systems which process national security information. This energy may relate to the original encrypted message or information being processed in such a way that it can lead to recovery of the plain text.

Laboratory and field tests have established that such compromising emanations can be propagated through space and along nearby conductors. The interception/propagation ranges and analysis of such emanations are affected by a variety of factors, i.e., the functional design of the information processing equipment, system/equipment installation, and environmental conditions related to physical security and ambient noise. The term “compromising emanations” rather than “radiation” is used because the compromising signals can, and do, exist in several forms such as magnetic- and/or electric-field radiation, line conduction or acoustic emissions.

The term TEMPEST is often used broadly for the entire field of Emission Security or Emanations Security (EMSEC). The term TEMPEST was coined in the late 1960s as a code name for the NSA operation to secure electronic communications equipment from potential eavesdroppers and, vice versa, the ability to intercept and interpret those signals from other sources.

The U.S. and NATO TEMPEST standards define three levels of protection requirements. First, there is the NATO SDIP-27 Level A and USA NSTISSAM Level I “Compromising Emanations Laboratory Test Standard.” This is the strictest standard for devices that will be operated in NATO Zone 0 environments, where it is assumed that an attacker has almost immediate access, such as a neighboring room that is one yard away.

Second is the NATO SDIP-27 Level B and USA NSTISSAM Level II “Laboratory Test Standard for Protected Facility Equipment.” This is a slightly relaxed standard for devices that are operated in NATO Zone 1 environments, where it is assumed that an attacker cannot get closer than about 20 yards.

Third is the NATO SDIP-27 Level C and USA NSTISSAM Level III “Laboratory Test Standard for Tactical Mobile Equipment/Systems.” This is an even more relaxed standard for devices operated in NATO Zone 2 environments, where attackers have to deal with about 100 yards worth of free-space attenuation, or equivalent attenuation through building materials.

So how would law enforcement stop potential attacks to the integrity of its mobile wireless data? The military thought a good place to start was with the construction of a Radio Frequency (RF) tight Tempest laptop docking station that holds the laptop in its Mine Resistant Vehicles. They went out to the various manufacturers of laptop docking stations to see what was out in the market, but it quickly became clear that nothing of this nature had ever been built for either military or law enforcement applications.

Precision Mounting Technologies (PMT) of Calgary, Alberta, Canada, is a leader in laptop docking stations for both law enforcement and military vehicles. Dr. Ken Dyck, PMT president, looked at this requirement and set to design and build a Tempest docking station unlike any before.

PMT has a long history of providing high quality police mobile computing systems all over the world and of providing the military with high quality mounting systems. All of PMT’s products are made out of aircraft-grade aluminum because once the docking station is assembled, the aluminum is as strong as steel but much lighter.

Machining aluminum is a slower process but more exact and much stronger. If you were to use folded sheet metal, you would have to remember that metal bent one way can also be bent back the other way. Why is this important? Consider the security of your laptop and data. Can you get the laptop out of the docking station simply by prying the sheet metal with a large screwdriver or pry bar? You can’t do this to a PMT aluminum docking station.

The difference with this Tempest system is that it had to be engineered from scratch; nothing like it ever existed before so there was nothing to use as an example. The hardest part of Tempesting the dock was designing a shroud that covered the docking station’s circuit board on the underside. The circuit board would be the primary source of RF leaks, so this component had to be the most robust and secure part of the dock, all while still allowing easy field access.

To ensure this in the design of the circuit board housing, PMT used double layer 1/8-inch aluminum to form the enclosure. The key to this enclosure being RF tight is the special custom machining that creates “lap-joints” to trap the escaping RF signal. The circuit board is a standard Panasonic circuit board with two com ports, four USB 2.0 EDR, one microphone, one speaker and one VGA. Cable security and stability are accomplished with a strain relief system called a hitch rail, another custom PMT design.

In military vehicles, electrical bonding is very important. Considering all the electrical noise going on inside the vehicle, this docking station had to be well-grounded, and as such, PMT engineered multiple grounding anchors on the dock itself. The Tempest docking station not only had to be totally electronically bonded but completely vibration and shock resistant to military specifications. This meant a specific G-Force was applied to the docking station, and the computer could not come out under any circumstances.

This level of testing is directly applicable to law enforcement applications. In several serious police vehicle accidents, the laptop has become a projectile inside the vehicle because the docking station failed to hold the police laptop secure after impact. Typical testing for police vehicle docking stations might involve a 60 mph head-on collision test, which is around 16gs of force. The military requirement for this Tempest docking station was 100 times that, and the laptop stayed secure. Your current docking station should provide this kind of crash protection for the officer.

The second part of the design was to make it water and sand resistant to MIL-STD-810F specifications. This meant actually placing the docking station under a shower of water for 10 minutes to ensure it continued to work as required. This was accomplished by the strict tolerances and tight machining specifications in the aluminum cutting process. All measurements must be exact as there is little room for excessive tolerances. All seals are made with military spec rubber, and all ports are sealed with removable custom rubber grommets.

Ruggedized notebooks and ruggedized docking stations have survived many documented motor vehicle incidents and can withstand much greater force today. Most manufacturers that claim to build rugged computers or docking stations have gravitated to a variation of a standards scheme set forth by the U.S. Armed Services, a leading user of rugged computing technology.

The MIL-STD-810F standards specify a variety of environmental tests that manufacturers can use to prove that equipment will survive in the field. Of these variables, those that are most relevant to rugged computing include humidity; contamination by fluids, salt fog, sand or dust; icing/freezing rain; explosive atmosphere (arcing/sparks); leakage; high/low temperatures; solar radiation; low pressure (altitude); shock; vibration and rain.

Currently, the armed services do not conduct actual tests or certify that rugged devices meet MIL-STD-810F standards. Instead, the armed services expect their suppliers of rugged computing equipment to assure or guarantee adherence to the standards. As a result, many rugged computing manufacturers are able to tout their devices as “MIL-STD-810F-compliant” when they meet only one or two of the testing criteria, and even if the device is never offered to or purchased by the armed services. Manufacturers often claim partial or near compliance with a particular MIL-STD-810F testing standard or otherwise overstate their device’s rugged characteristics. This is why it is critical that claims be tested and proven.

In the case of PMT’s Tempest docking station, it has been tested beyond any other product in its class. It has survived the ultimate test in the theater of war and provided our soldiers with the best possible solution available today. In 2009, the Canadian Military purchased 1500 PMT Tempest docking stations for use in conjunction with the Panasonic CF-30 notebook for deployment in Afghanistan.

As law enforcement uses more wireless technology, the risk of data interception becomes more relevant. It’s good to know that at this point in time, the good guys have a system that will hopefully keep the bad guys from ever getting their hands on any sensitive information.

Sergeant Brad Brewer is a 22-year member of the Vancouver Police Department. He sits on the Ford Police Advisory Board and regularly gives presentations at law enforcement conferences on mobile computing, wireless technology and police vehicle ergonomics. He can be reached at

Published in Law and Order, Mar 2010

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