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IBM Q system in development with working 50 qubit processor

www-03.ibm.com

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Re: IBM Q system in development with working 50 qubit processor

#31

Post by vtomole »

zamalek wrote: post #21

What are they doing about error correction? Not that it makes this any less impressive (everything starts somewhere ), are they simply ignoring the problem?

It's a bit too early for quantum computers to do fault-tolerant (error corrected) computation. This is because you need more than one physical qubit to make a logical (error corrected) qubit. You need 7 physical qubits to encode a logical qubit if you use the Steane code [0]. So with 50 qubits, they could theoretically make 7 error corrected qubits.

[0]: https://en.wikipedia.org/wiki/Steane_code

Re: IBM Q system in development with working 50 qubit processor

#32

Post by Zaak »

jayess wrote: post #27
darawk wrote: post #9

Earlier quoted context omitted.

Quantum computers don't break all encryption. There's no risk of that, fortunately.

Please expand on that. What encryption is vulnerable and what isn't?

Symmetric encryption will need to double key lengths, such as using 256-bit AES keys instead of 128-bit.

All currently popular forms of asymmetric / public key encryption (including RSA and ECC) are vulnerable to quantum attack.

Re: IBM Q system in development with working 50 qubit processor

#33

Post by bob_theslob646 »

Cyph0n wrote: post #26
derwiki wrote: post #20

Earlier quoted context omitted.

What stands out to you in the last 20 years?

IBM has been awarded more patents per year than any other company for the last 24 years[1]. In 2016 alone, IBM published ~22 patents per day, and ended up being ~2500 patents ahead of Samsung (#2). [1]: http://www-03.ibm.com/press/us/en/pressrelease/51353.wss

Does that necessarily mean that is impressive?( I know it is, I am just asking for someone who may not understand what having that type of scale of IP enables a company to do.)

Re: IBM Q system in development with working 50 qubit processor

#34

Post by marcosdumay »

mtgx wrote: post #13
tnash wrote: post #7

At what point do we no longer trust public key cryptography (RSA)? Where's the break point?

> It is estimated that 2048-bit RSA keys could be broken on a quantum computer comprising 4,000 qubits and 100 million gates. Experts speculate that quantum computers of this size may be available within the next 20-30 years. https://www.entrust.com/wp-content/uploads/2013/05/WP_Quantu... The paper is from 2009, so ~2030 to break 2048-bit RSA seems about right. If they can double the number of qubits every two years,…

From the Wikipedia timeline[1], it seems to be growing linearly.

1 - https://en.wikipedia.org/wiki/Timeline_of_quantum_computing

Re: IBM Q system in development with working 50 qubit processor

#35

Post by agumonkey »

zamalek wrote: post #21

What are they doing about error correction? Not that it makes this any less impressive (everything starts somewhere ), are they simply ignoring the problem?

I just saw a talk by I forgot which bell labs engineer was on the transistor team. He told it took two or more years to get the errors to a useful level. It's easy to think transistor are magic solid devices, they were not.

Re: IBM Q system in development with working 50 qubit processor

#36

Post by gruez »

mtgx wrote: post #13
tnash wrote: post #7

At what point do we no longer trust public key cryptography (RSA)? Where's the break point?

> It is estimated that 2048-bit RSA keys could be broken on a quantum computer comprising 4,000 qubits and 100 million gates. Experts speculate that quantum computers of this size may be available within the next 20-30 years. https://www.entrust.com/wp-content/uploads/2013/05/WP_Quantu... The paper is from 2009, so ~2030 to break 2048-bit RSA seems about right. If they can double the number of qubits every two years,…

>Also, you have to consider that once you get a quantum computer that can break 2048-RSA, you'll be able to break all the encrypted communications you've stored in the past few years, too

isn't that what PFS is supposed to prevent?

Re: IBM Q system in development with working 50 qubit processor

#37

Post by jd007 »

gnode wrote: post #22
Zaak wrote: post #15

Earlier quoted context omitted.

If I remember correctly, it takes a quantum computer with roughly 2N qubits to break N-bit RSA. So we should be ok until thousand-qubit systems are being developed. Increasing key lengths is a short-term workaround, but the real solution is post-quantum public key encryption, which is currently an area of active research.

Do you know what the implications are for symmetric ciphers or [elliptic curve] Diffie-Hellman key exchange? I.e. will forward secrecy still hold up against such future quantum computing?

SIDH (https://en.wikipedia.org/wiki/Supersingular_isogeny_key_exch...) is one of the few popular post-quantum variants of DH key exchange, and it supports forward secrecy as well.

Re: IBM Q system in development with working 50 qubit processor

#38

Post by mtgx »

zamalek wrote: post #21

What are they doing about error correction? Not that it makes this any less impressive (everything starts somewhere ), are they simply ignoring the problem?

They don't seem to be ignoring it. They are using this idea of "quantum volume" which incentivizes them to take into account both the number of qubits and the error rate to determine how useful their quantum computer is in solving problems:

https://www.research.ibm.com/ibm-q/resources/quantum-volume....

Re: IBM Q system in development with working 50 qubit processor

#39

Post by mtgx »

gruez wrote: post #36
mtgx wrote: post #13

Earlier quoted context omitted.

> It is estimated that 2048-bit RSA keys could be broken on a quantum computer comprising 4,000 qubits and 100 million gates. Experts speculate that quantum computers of this size may be available within the next 20-30 years. https://www.entrust.com/wp-content/uploads/2013/05/WP_Quantu... The paper is from 2009, so ~2030 to break 2048-bit RSA seems about right. If they can double the number of qubits every two years,…

>Also, you have to consider that once you get a quantum computer that can break 2048-RSA, you'll be able to break all the encrypted communications you've stored in the past few years, too isn't that what PFS is supposed to prevent?

PFS can slow it down a bit, but not much. Assuming before PFS everyone changed their keys every 3 years, and with PFS they change them every 2 weeks, then it should be about 80x harder (slower to break the encryption). 80x harder may seem like a lot but it's not that much in the context of quantum computers.

Also, PFS uses 256-bit ECC, which only requires a 512-qubit quantum computer to break it. So it's possible that a 4,000 qubit quantum computer, or even a smaller one, could break ECC with PFS even faster than it can break 2048-bit RSA.

Re: IBM Q system in development with working 50 qubit processor

#40

Post by krastanov »

rbanffy wrote: post #3

I look forward to supercool (no pun intended) qSeries mainframes and whatever wild OSs they'll run. Right now, it looks like it's a batch processing like thing, with a single problem using the machine at any given time with long setup/teardown times.

Quantum computers will probably be simply addon hardware to classical computers for very long time. If a classical computer can solve something "efficiently", a quantum computer will not provide any speedup (but there are problems that are practically solvable only on quantum computers).
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