(PhysicsWorld) The mood among quantum physicists is generally buoyant about the possibility a large-scale quantum computer will become a reality. There’s just one problem: when that happens, it may break the Internet. Most of today’s encryption systems are built around “trapdoor functions”: mathematical problems that are easy to solve if you have a certain piece of knowledge, but hugely difficult if you don’t. Quantum computers are different and can factor large numbers much more efficiently.
The impending failure of widely used encryption methods constitutes a “quantum Y2K moment” – a latter-day counterpart to the bug that, 20 years ago, left experts scrambling to fix systems and computer code that could not handle dates beyond the year 1999. There is one crucial difference between the quantum Y2K moment and its classical cousin. Whereas the original bug was well-localized in time, the quantum version is, appropriately, fuzzier. One source of uncertainty is that nobody knows for sure when a cryptographically useful quantum computer will be built.
The good news is that a massive information security crisis is far from inevitable. “The reason there was no Y2K disaster is because people put money into it and worked on it and fixed the problem,” notes Kenny Paterson, an information security expert at Royal Holloway, University of London, UK.