Toughened Technology

TEMPEST

A further measurement of ruggedness, arguably the toughest of all, is the TEMPEST certification, although this is seldom encountered by civilians. A classified standard, the TEMPEST assessment deals with how resistant equipment is to electromagnetic eavesdropping.

During normal operation, electronic devices (in particular computers and screens) emit electromagnetic radiation. Theoretically, this can be remotely intercepted and used to read small but critical parts of the operation of the computer, or the data being processed by the system.

TEMPEST concerns originally arose during the cold war, with TEMPEST being used as a meaningless codeword to cover any kind of 'compromising radiation' that electrical equipment might emit (entertainingly discussed in a partially declassified NSA document from the 1960s [PDF]).



As technology has evolved, so has TEMPEST screening, and it was recently suggested that it is now an acronym for 'Telecommunications Electronics Material Protected from Emanating Spurious Transmissions'. As TEMPEST is a classified standard, it's hard to find any detailed information about it, but the highest level of TEMPEST goes by the catch name of NATO SDIP-27 Level A. To achieve this certification, a system must have complete electromagnetic shielding.

For instance, this may mean that the cables have to be coated in copper foil or the components might be earthed to the chassis. It's possible to find a few companies on the Web selling TEMPEST equipment, ranging from screens to PCs to printers, and these will often be based upon standard consumer equipment, upgraded and altered to meet the relevant standard.

Ruggedised laptops are all well and good but the significant strides made in computer hardiness over recent years aren't that apparent to the average consumer. Tougher and more resilient computers have started to feature in devices, whereas before they would have been considered too fragile or unreliable to be used.

The most obvious example of how today's tougher systems are making their presence felt is in the military. Some of the
first computers built, such as the Colossus at Bletchley Park, were built with military use in mind and the military has always been close to the cutting edge when it comes to pushing the boundaries for computer use. However, the implementation of computers close to or actually on the battlefield brings with it problems of its own. In an office or home environment there are viruses, spyware and the occasional coffee spill to worry about. Under combat conditions, the threats become all the more dangerous, if a little less sophisticated.

Many computers used in combat are embedded in vehicles; this gives them the advantage of protection from the elements as well as a stable mounting that will afford a degree of protection from the elements. It exposes them to damage from vibrations, though, and this may cause components to become loose over time. This can be countered by shock-absorbent mountings but a more effective method is to reduce the amount of components used in the first place.

Streamlining a computer to make it more rugged is a valid design approach, so it's obvious that the military is interested in Thin Client Technology. In this kind of design, the system is a simple, low-power unit. It's then connected to a Fat Client, which acts as a server for multiple systems, providing files, data and even processing power for many client computers.