Pair win Turing Award for computer encryption breakthrough

A US physicist and a Canadian computer scientist have won this year's Turing Award for their invention of a form of seemingly unbreakable encryption.

Charles H Bennett and Gilles Brassard's work, which dates back to 1984, is known as quantum cryptography and has "redefined secure communication and computing", the award's body said.

Scientists believe their work will be central to electronic communications in a world that depends heavily on data-sharing, but which for years has been trying to develop more powerful quantum computers.

The Turing Award, named after the mathematician and code-breaker Alan Turing, is known as the "Nobel Prize of computing". It comes with a $1m (£800,000) prize.

Bennett, 82, is a fellow at technology company IBM in New York, while Brassard, 70, is a professor at the University of Montreal. The pair met by chance whilst attending an academic conference in Puerto Rico in 1979.

Bennett is reported to have approached the computer scientist as they were swimming during a break to suggest the idea of developing a banknote that could never be forged.

It heralded decades of co-operation, during which the two men developed a technique based on quantum physics - the behaviour of particles of matter, including electrons and photons.

Current encryption technology relies on complex mathematical combinations, but many scientists believe that the arrival of quantum computers will make this insecure.

By contrast, Bennett and Brassard's theory - known as BB84 - shows that any attempt to hack or copy their quantum encryption key changes the very behaviour of its elements, making replication impossible.

In the announcement on Wednesday, the Association of Computer Machinery - the body that awards the Turing Award, praised their work as a "pathway toward securing digital communications in the decades ahead".