security
Keeping radio traffi c secure
Alun Lewis looks into the security features of TETRA digital mobile communications technology against the background of political and other developments in the wider world
S
ince the dawn of recorded history, people have found ever more ingenious ways to try and keep their communications secure from prying eyes and ears. Over the past century or so, increasingly advanced
technologies – often involving the cutting edges of mathematics, physics and engineering – have been deployed both by those looking to safeguard their secrets and those seeking to crack them. From the World War 2 codebreakers at the UK’s top-secret
Bletchley Park military intelligence centre – whose work arguably saved millions of lives and laid the foundations for modern computing – to today’s use of the near-magical properties of quantum physics to distribute coding keys securely over fi bre-optic networks, a quiet arms race has been constantly running in the background. Quiet, that is, until some high-profi le event occurs that reminds everyone of the implicit vulnerabilities of once-trusted devices, services and systems. For anyone involved in designing or operating mission-
Alun Lewis is a journalist and
telecoms consultant and is a regular contributor to TETRA TODAY
16
critical communications networks, having a healthy sense of controlled paranoia is very probably a useful trait. Although TETRA benefi ts from having high-grade security options built into it from Day One, a number of changes are underway in the wider world that demand a constant awareness and reassessment of threats as conditions change.
Human weakness If the history of cryptography teaches us anything, it is that human factors – such as complacency, poor training and exploitable human frailties – often pose more of a direct threat to security than any new technology. T at said – and just as has happened in the world of
Internet security – the ready availability of cheap processing power and the ability of hackers to share information across the Web is already challenging historically secure systems. When TETRA was fi rst introduced, one of its attractive
points for the emergency services was that it stopped criminals and the media in search of a hot story from listening in on scanners. While communications over TETRA using the TETRA Encryption Algorithm (TEA) family of standards do remain secure, projects such as Osmocom’s TETRA open source software initiative have already now made it possible to monitor unencrypted TETRA speech channels using only a laptop and an appropriate USB dongle. Unoffi cial reports suggest that hackers have already
used this to listen in to and record tram drivers on Berlin’s BVG transport network. While not earth-shattering in its consequences, this exploit does simply demonstrate that as soon as you erect a wall, there will always be people with suffi cient curiosity, time and energy to expend in trying to
TE TRA TODAY Issue 5 2011
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