Is anyone listening in?

Dynamic phone call encryption to throw hackers off track

A dynamic encryption system that changes with every call to confuse possible eavesdroppers has been developed by Danish researchers.

The system, to be launched commercially later this month, builds on the currently prevailing encryption system AES and adds extra layers of protection that change dynamically with every call.

“When my phone calls you up, it selects a system on which to encrypt the conversation,” explained Professor Lars Ramkilde Knudsen from the Technical University of Denmark, who invented the system.

“Technically speaking, it adds more components to the known algorithm. The next time I call you, it chooses a different system and some new components. The clever thing about it is that your phone can decrypt the information without knowing which system you have chosen. It is as if the person you are communicating with is continually changing language and yet you still understand,” he said.

As the encryption method changes with every call, possible eavesdroppers are thrown off the track and left unable to decipher the key.

Although the currently prevailing AES method, selected by the US government in a 1997 competition, encrypts telephone calls to make them unintelligible to possible eavesdroppers, this encryption has gaps as it not only uses the same key all the time but also doesn’t cover the whole route of the telecommunications signal.

“Today, the telephone conversations are not encrypted all the way from phone to phone, and if a third party has access to one of the telephone masts through which the call passes, they can listen in,” said Lars Ramkilde Knudsen.

To allow companies to actively protect themselves against cyber espionage, Knudsen established Dencrypt, a small company, which aims to commercialise his invention.

According to a 2014 report by an IT-security firm McAfee, companies in the US alone lose about £100bn every year due to industrial espionage targeting their know-how, trade secrets and research results.

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