## Post-Quantum Algorithms

NIST has organized a competition for public-key algorithms secure against a quantum computer. It recently published all of its Round 1 submissions. (Details of the NIST efforts are here. A timeline for the new algorithms is here.)

Lisa • December 27, 2017 8:44 AM

Sorry, am I missing something here? Has the quantum decoherence problem been sufficiently solved?

I last heard that physicists do not know yet how conherenent qubits in a general purpose quantum computer capable of running Shor’s algorithm and other similiar public key busting routines, will scale with the increasing number of qubits. The current record for quantum factoring uses at most 4-6 qubits, and took 2 years to set up.

Many still think that this may scale exponentially, such that it may require more energy than in our galaxy, or more time than trillions of years, to set up a sufficiently powerful quantum computer and operate in such a manner capable of breaking a single large public key.

Until we know that public key busting quantum computing is even physical possible/practical, this seems like a science fiction threat that we should not concerns ourselves with any more than we do with other sci-fi threats to crypto such as time travelling, parallel universes, or hyper-intelligent AI.

Actually the last threat seems to be much more of a practical concern than quantum computing or the other sci-fi threats are, since advance intelligence (be it AI or a lucky and brilliant humans) are much more likely to find exploits against trapdoor functions which are at the heart of all public key cryptography.

Personally until there is some physical experimental evidence regarding qubit scaling for a general purpose quantum computer, I think that more research effort should be spent on understanding and validating existing public key crypto and also developing new and better trap door functions, than just focus solely on quantum resistance alhorithms.