Think your cellphone calls are secure? Think again

Stuart Corner
Monday, 26 June 2006 13:21

Opinion and Analysis

Back in the good old days of analogue cellphones security was non-existent and there were a few very high profile amateur intercepts. Remember Prince Charles' interesting conversation with Camilla Parker Bowles?
When GSM came in we were told that all conversations were encrypted with a highly secure algorithm and to make it more secure even details of the algorithm were kept secret.

There were many who disagreed with this approach, arguing that exposing the algorithms to public scrutiny would enable their strength to be tested by the cryptographic community at large and  any weaknesses to be discovered and remedied.

These views proved all too true. Details did indeed leak out in the late 1990s and a few years ago a group of Israeli academics stunned the cryptographic community by unveiling, at a conference, very practical techniques for intercepting GSM calls and 'spoofing' cellphones.

Today, it is perfectly possible, but pricey and prohibited, to buy off-the-web a unit that will enable any calls in its vicinity to be intercepted. Just how easy this is has been brought home to families of British soldiers serving in Iraq: they have received nuisance and threatening calls from people with thick middle-eastern accents.

The army, according to UK's Daily Telegraph has issued a warning to soldiers serving in Iraq to be cautious about using their cellphones to call home. "Investigations indicate that the 'callers' of these nuisance calls have acquired the numbers rom personnel using their own mobile phones. This is fairly easy using today's technology."

Bet you won't find that information in the small print on your cellphone contract! Yet it does suggest that there is very real cause for concern.  And the threat is sufficiently serious to create a market for prevention.  At the CeBit show in Sydney last month, Melbourne based SecureGSM (www.securegsm.com) was promoting its technology for Microsoft-based smartphones that adds a further layer of encryption to the conversation (of course it only works if both phones are using it).

Of course, it is one thing to scan the airwaves for any call made to a UK or Australian number from Iraq and make nuisance calls to that number and an entirely different matter to try and intercept a specific conversation for purposes such as industrial espionage.  But what was it Andy Grove said? "Only the paranoid survive."