Chaos-based communications successfully tested in commercial environment

Brussels, 29 Nov 2005

Researchers from the EU funded OCCULT project have succeeded in sending data within a chaotic carrier through a commercial fibre-optic network, illustrating the potential of optical chaos communication for protecting the transmission of data. The conclusions of the experiment, which took place in Athens, Greece, have been published in the scientific journal Nature.

This cutting-edge technique, which employs synchronised laser emitters and receivers to encrypt information at the hardware level, represents an important qualitative upgrade to existing security systems for protecting the transmission of data. Until now, chaotic communication had been demonstrated in the lab but not in a genuine commercial network.

Pere Colet, a member of the OCCULT project team from the Spanish National Research Council (CSIC) at the Mediterranean Institute for Advanced Studies (IMEDEA), said that 'the work represents the first practical demonstration of the use of chaos to encript a message in optical fibre networks'.

To increase the levels of security and privacy, the team used a message carrier generated by a semiconductor laser operating in a chaotic regime through a 120 km optical fibre network. Thanks to this method, Dr Colet explains, 'the message is transmitted at speeds of 1 gb/s, and is recovered with a transmission bit error rate smaller than 0.0000001'.

The ever-growing demand for communications services is being supported by a fast increase in transmission and switching capacity in networks. The two major challenges in these networks are privacy and security. These two issues have been dealt with, until now, by using public key cryptosystems. These systems can use a secret parameter, known as the 'key', or they can encipher the message directly. However, the encryption of information by means of these algorithms presents risks, since with sufficient time it is possible to break the security keys. Moreover, the continuous increase of computer speed threatens the safety of these procedures.

The idea of OCCULT was to use hardware, that is the emitters and receivers of the information, to carry out the encryption. These could be used in combination with software encoding to create two levels of security. The technique researched and evaluated by the OCCULT project relies on having two sets of semiconductor lasers that are virtually identical to send and receive information over fibre-optic cables. The light transmitted by these lasers is non-linear and chaotic so only a receiver synchronised with the emitter can decode the data, making it almost impossible for the transmission to be decrypted by someone other than the intended recipient.

For high security transmissions the lasers need to operate with a tolerance level of just one or two per cent, something that can only be achieved if they are made with the same equipment and the same components at the same time. The lasers not only have to come from the same batch of semiconductors, but literally be produced side-by-side to make them compatible. According to the project coordinator, Claudio Mirasso from the University of the Balearic Islands (UIB), 'anyone wanting to break the encryption has to know as much as the people using it and have a virtually identical device.' He adds: 'We've demonstrated that an extremely high level of security can be achieved because cracking the system would require adjusting 200 or 300 parameters.'

OCCULT, which stands for 'optical chaos communications using laser-diodes transmitters' was funded with 1.74 million euro by the information society technologies programme of the Sixth Framework Programme. The project, completed in September 2004, gathered, research centres and industrial partners from Greece, France, Italy, Spain, Germany, Switzerland and the UK for three years.

The project participants, together with new partners, have now proposed a new activity aIMED at bringing the results of OCCULT into the real world. They have submitted an expression of interest for a follow-up project, INTOCCULT. If accepted, the partners believe that they could get the technology to the stage of industrial prototype in about two years.

As the technique can be used over existing fibre-optic cables and is relatively cheap to employ, with the only additional components being the emitter and receiver, the project participants believe that it has vast market potential.

For further information, please contact:
Claudio Mirasso
Departament de Fisica
Universitat de les Illes Balears
E-07122 Palma de Mallorca
Spain
Tel: +34-971-1783
Fax: + 34-971-173426
E-mail: claudio@galiota.uib.es

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