jm + quantum-computing   2

Scott Aaronson on Google's quantum supremacy leaked paper
It seems a paper between Google and NASA accidentally leaked a couple of days ago, saying that a group at Google has now achieved quantum computational supremacy with a 53-qubit superconducting device. According to Scott Aaronson, a noted quantum-computation expert, this is a Big Deal and a significant moment in scientific progress:
It’s like, have a little respect for the immensity of what we’re talking about here, and for the terrifying engineering that’s needed to make it reality. Before quantum supremacy, by definition, the QC skeptics can all laugh to each other that, for all the billions of dollars spent over 20+ years, still no quantum computer has even once been used to solve any problem faster than your laptop could solve it, or at least not in any way that depended on its being a quantum computer. In a post-quantum-supremacy world, that’s no longer the case. A superposition involving 250 or 260 complex numbers has been computationally harnessed, using time and space resources that are minuscule compared to 250 or 260.

I keep bringing up the Wright Flyer only because the chasm between what we’re talking about, and the dismissiveness I’m seeing in some corners of the Internet, is kind of breathtaking to me. It’s like, if you believed that useful air travel was fundamentally impossible, then seeing a dinky wooden propeller plane keep itself aloft wouldn’t refute your belief … but it sure as hell shouldn’t reassure you either.
google  programming  quantum-computing  qubits  future  science  qc  history  research 
21 days ago by jm
A Guide to Post-Quantum Cryptography
Post-quantum cryptography is an incredibly exciting area of research that has seen an immense amount of growth over the last decade. While the four types of cryptosystems described in this post have received lots of academic attention, none have been approved by NIST and as a result are not recommended for general use yet. Many of the schemes are not performant in their original form, and have been subject to various optimizations that may or may not affect security. Indeed, several attempts to use more space-efficient codes for the McEliece system have been shown to be insecure. As it stands, getting the best security from post-quantum cryptosystems requires a sacrifice of some amount of either space or time. Ring lattice-based cryptography is the most promising avenue of work in terms of flexibility (both signatures and KEM, also fully homomorphic encryption), but the assumptions that it is based on have only been studied intensely for several years. Right now, the safest bet is to use McEliece with Goppa codes since it has withstood several decades of cryptanalysis.
cryptography  crypto  post-quantum-crypto  pqc  quantum-computing  via:el33th4xor  security  algorithms 
october 2018 by jm

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