‘Perfect secrecy’ achieved in computing as scientists make first unhackable system

Professor Andrea di Falco - University of St Andrews 
Professor Andrea di Falco - University of St Andrews

The world’s first uncrackable security system, which even quantum computers could not hack, has finally been developed by researchers.

Computer scientists had feared that the dawn of quantum computing would allow even the most fiendishly-encrypted data to be easily decoded, causing a major headache for banks, government agencies and communications providers.

As far back as 1917, scientists had proposed that ‘perfect secrecy’ could be achieved if it was possible to change the key which encrypts a message each time, based on the message itself. 

Now, the University of St Andrews and international partners, have done just that, creating a type of chip which effectively creates a one-time-only key from the data being sent, scrunching it all up before sending, in a way that could never be hacked.

The digital information is first stored as light, then is passed through a specially engineered silicon chip containing complex structures which bend and refract the light, scrambling the information.

First author, Professor Andrea di Falco of the School of Physics and Astronomy at the University of St Andrews, said: “It’s the equivalent of standing talking to someone using two paper-cups attached by string. If you scrunched up the cups when speaking it would mask the sound, but each time it would be scrunched differently so it could never be hacked.

“This new technique is absolutely unbreakable. People are becoming increasingly concerned about the privacy of their data so this is future-proofing their security.”

Quantum computing represents such a leap forward because it frees machines from their binary coding. While computer bits can only operate as ‘0’ or ‘1’, quantum bits (qubits) can exist in multiple states - a phenomenon known as superposition, which ramps up computing power exponentially.  

Qubits are made from tiny particles, such as the electrons of phosphorus atoms, which have ‘spin’ and point magnetic north or south (the equivalent of 0 and 1), but also multiple directions in between, like a compass needle.

While pointless for tasks such as running word processors or web streaming, their exponential power would render today's encryption software obsolete.

Although true quantum computers are still a long way off, earlier this year, Google claimed it had achieved ‘quantum supremacy' after solving a problem that would take a classical computer far too long to complete. 

Security experts were concerned that cyber-terrorists were already storing up information ready to break once quantum computing is a reality. But the new breakthrough would stop hackers in their tracks. 

Leader of the study, Dr Andrea Fratalocchi, Associate Professor of Electrical Engineering at King Abdullah University of Science and Technology, in Saudi Arabia, said: “With the advent of more powerful and quantum computers, all current encryptions will be broken in a very short time, exposing the privacy of our present and, more importantly, past communications.

“For instance, an attacker can store an encrypted message that is sent today and wait for the right technology to become available to decipher the communication.

“Implementing massive and affordable resources of global security is a worldwide problem that this research has the potential to solve for everyone, and everywhere. If this scheme could be implemented globally, crypto-hackers will have to look for another job.”

The research was published in the journal Nature Communications.