MIT has created the first five-atom quantum computer with the potential to crack the security of traditional encryption schemes – if the cat can be bothered getting out of the box and chasing the numbers,
Quantum computing relies on atomic-scale units, or “qubits,” that can be simultaneously 0 and 1. It typically takes about 12 qubits to factor the number 15, but researchers at MIT and the University of Innsbruck in Austria have found a way to pare that down to five qubits, each represented by a single atom.
By using laser pulses to keep the quantum system stable by holding the atoms in an ion trap, the new system promises scalability as well, as more atoms and lasers can be added to build a bigger and faster quantum computer able to factor much larger numbers.
However that tiggers factorisation-based methods such as RSA, used for protecting credit cards, state secrets and other confidential data. This is because they are based on Shor’s algorithm, the most complex quantum algorithm known to date. Fifteen is the smallest number that can meaningfully demonstrate Shor’s algorithm. But this computer returned the correct factors with a confidence better than 99 percent.
Isaac Chuang, professor of physics and professor of electrical engineering and computer science at MIT said that Shor’s algorithm is the most complex quantum algorithm known to date and it is now possible to go to a lab and build a computer which can crack it.
“It might still cost an enormous amount of money to build—you won’t be building a quantum computer and putting it on your desktop anytime soon—but now it’s much more an engineering effort, and not a basic physics question,” Chuang added.
At the moment the MIT machine scalable enough but that is another engineering problem which will be fixed. Once the apparatus can trap more atoms and more laser beams can control the pulses there is no physical reason why that is not going to be in the cards.
Already though that does mean that nation states probably don’t want to publicly store your secrets using encryption that relies on factoring as a hard-to-invert problem. As quantum computers start coming out those old secrets will be unencrypted, Chuang said.