Today, encryption is hotter than ever. From the Wikileaks documents it is clear time and again that governments frequently hack into communication systems that are indispensable for its civilians. Therefore services such as WhatsApp encipher messages between users, so that they are illegible to other parties. Such enciphering - also called encryption - is however not infallible. That is why it is crucial that encryption systems are continuously improved upon.
‘Classic’ encryption relies on the use of mathematical algorithms. These can be seen as a kind of digital keys that allow for information to be enciphered and deciphered. Although in practice this works fairly good, any powerful enough computer can determine such a key through a so called brute force attack.
Researchers of the Applied Physics Research Group (APHY) of VUB have now developed an alternative method to create keys that are truly uncrackable. They made use of chaos synchronisation, whereby a chaotic signal - such as noise on an analog TV - seems irregular, but actually originates in a mathematically defined or ‘deterministic’ system.
Advantages over traditional encryption
In short, the system is based on the exchange of a chaotic signal between senders and receivers. On the receiving end a second chaotic system is synchronised upon that of the sender. Although the signal from this second system is determined by the transmitting signal, it has practically no demonstrable relations with the signal from the sender’s side. This is what is known as generalised synchronisation. The actual message is simultaneously encoded with a key that is derived in the same way from the chaotic signal on the sender’s side. Thanks to generalised synchronisation between transmitter and receiver the message can then be decrypted and read on the receiver’s side.
The systems offers various advantages as opposed to traditional encryption systems. It doesn’t require a lot of computing power to encrypt a message, allowing real time use. And since the key is generated from a chaotic signal, it is impossible an identical key will ever be created. These qualities result in an extremely attractive encryption system according to the researchers.
Ready for implementation
‘We have experimentally shown that generalised synchronisation with very low correlations can be used for generating and distributing high quality encryption keys,’ says Lars Keuninckx, a member of the research group. ‘An added bonus is that the system can be implemented both with contemporary electronics and photonics (fiber optic materials).’
The study was performed in close collaboration with researchers from the Instituto de FÃsica Interdisciplinar y Sistemas Complejos (IFISC, University of the Balearic Islands) and Optique Nonlinéaire Théorique van de ULB.
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