Earlier quoted context omitted.
Even for that to work you need a good random number generator
That's pretty trivial. xor a video camera with AES and no one is decrypting that ever.
And, famously, the camera is pointing at a lava lamp, ha ha.
Willow, Our Quantum Chip
471–480 of 557 posts
Re: Willow, Our Quantum Chip
#472Earlier quoted context omitted.
It's in the article. Random circuit sampling benchmark: https://research.google/blog/validating-random-circuit-sampl...
Is it really fair to call that "computation"? I am definitely not an expert, but it seems they are just doing a meaningless operation which happens to be trivial on a quantum computer but near-impossible to simulate on a classical computer. To me that sounds a bit like saying my "sand computer" (hourglass) is way faster than a classical computer, because it'd take a classical computer trillions of years to exactly si…
It's different from your hourglass in that the computer is controllable. Each sampled random circuit requires choosing all of the operations that the computer will perform. You have no control over what operation the hourglass does.
It won't be factoring large numbers yet because that computation requires the ability to perform millions of operations on thousands of qubits without any errors. You need very good error correction to do that, but luckily that's the other thing they demonstrated. Only when they do error correction, they are basically combining their system down into one effective qubit. They'll need to scale by several orders of magnitude to have hundreds of error corrected qubits to do factoring.
Re: Willow, Our Quantum Chip
#473Newbie's question: how far is the RCS benchmark from a more practical challenge such as breaking RSA? The article concludes by saying that the former does not have practical applications. Why are they not using benchmarks that have some?
There are already companies selling 5,000+ qubit quantum systems to the NSA. I would assume they are already using it for that in the huge data center in Utah.
Which companies? And how big an RSA key do 5,000+ qubit quantum systems break?
Re: Willow, Our Quantum Chip
#474Earlier quoted context omitted.
The required number of qubits to execute Shor’s algorithm is way larger than 2500 qubits as the error ceiling for logical qubits must decrease exponentially with every logical qubit added to produce meaningful results. Hence, repeated applications of error correction or an increase in the surface code would be required. That would significantly blow up the number of physical qubits needed.
He’s quoting the number of logical qubits (which is 1024 IIRC, not 2500), after error correction. ETA: Wikipedia 2330 qubits, but I'm not sure it is citing the most recent work: https://en.wikipedia.org/wiki/Elliptic-curve_cryptography#ci...
The most recent result on reducing the number of logical qubits is [1]. They show how to use residue arithmetic to factor n bit numbers using n/2 + o(n) logical qubits (they give the example of 1730 qubits to factor a 2048 bit number).
Re: Willow, Our Quantum Chip
#475Re: Willow, Our Quantum Chip
#476Earlier quoted context omitted.
> so there's a case to be made for switching to quantum-resistant cryptography (like lattice-based cryptography) sooner rather than later. This. People seems to think that because something is end to end encrypted it is secure. They don't seem to grasp that the traffic and communication that is possibly dumped/recorded now in encrypted form could be used against them decades later.
Well. Yes, but currently there are no well tested (ie. recommended by the ITsec community) post-quantum cryptosystems as far as I understand. https://crypto.stackexchange.com/a/61596 But ... AES is believed to be quantum-safe-ish, so with perfect forwards secrecy this exact threat can be quite well managed. The currently best known quantum attack on AES requires a serial computation of "half of key length" (Grover's…
Signal and Apple both use post-quantum.
Re: Willow, Our Quantum Chip
#477Can't wait for Google to release a breakthrough paper in 5 years just for the authors to leave and build OpenQuant
Re: Willow, Our Quantum Chip
#478Earlier quoted context omitted.
Perfect forward secrecy doesn't work that well when NSA motto is - store everything now decrypt later. If they intercept the ephemeral key exchange now they can decrypt the message 10 or 50 years later.
Diffie Hellman doesn’t ever send the key over the wire, that’s the point. There is nothing to decrypt in the packets that tells you the key both sides derived. Unless they break ECDHE, it doesn’t matter if RSA gets popped.
According to the top image on the Wikipedia page, Diffie Hellman does send the public key over the wire.
https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exc...
Re: Willow, Our Quantum Chip
#479Newbie's question: how far is the RCS benchmark from a more practical challenge such as breaking RSA? The article concludes by saying that the former does not have practical applications. Why are they not using benchmarks that have some?
There are already companies selling 5,000+ qubit quantum systems to the NSA. I would assume they are already using it for that in the huge data center in Utah.
Source?