[Crypto-chi] Looks like our cryptoparties may be all for naught

[jen]

As Eviljoel says, the prototype quantum computers that we know currently
exist can only factor small integers - classical computers are right now
still your best bet at factoring big numbers. For example, current
quantum computers can factor ~8-bit numbers, but classical computers can
factor 768-bit numbers (in a year [0]). So unless one is using an RSA
modulus of 15, one is probably pretty alright versus quantum computers
(though not against classical computers... or human children and their
pesky arithmetic skills). Of course, this is all based on public
information. It is possible that some agency with an $11B budget for
cracking crypto might have a greater capability, though I doubt even
they can do much more with respect to quantum computation.

With that said, a lot of interesting academic work is going on to make
cryptosystems that are strong against adversaries with both classic and
quantum computers. Many ideas like lattice-based cryptography that your
article mentions toward the end have been around for a long time but are
getting renewed interest because of this threat. One of the main
problems right now for at least lattice-based crypto is that it's slow
and thus impractical. And even when we do have cryptosystems that are
both practical and quantum-resistant, it's a long and frustrating path
to having such a system be deployed everywhere, as we've seen when
trying to migrate away from weak ciphers like RC4 [1].

If anyone is particularly interested in this topic, I recommend checking
out a nice book that Dan Bernstein and others have written on various
future PK cryptosystems (including lattices) [2].

Best,

Jen

[0] https://eprint.iacr.org/2010/006.pdf
[1] https://blog.cloudflare.com/killing-rc4-the-long-goodbye/
[2] https://www.springer.com/mathematics/numbers/book/978-3-540-88701-0

eviljoel wrote:
> Hey Joe,
> 
> It is generally believed that a quantum computer that can do non-trivial
> computation is still at least several years away (if not 10s or 100s of
> years away).  When that happens, I am sure we'll move to quantum
> cryptography.
> 
> Joel Luellwitz
> 
> 
> On 11/17/2014 11:48 PM, joe fuentes wrote:
>> I came across this and wanted to share with you. 
>>
>> It sez quantum computing will make mince pie meat out of crypto.
>>
>> Wot are your thoughts on this? Post please.
>>
>> /Wot do I think?/ *The end is nigh!*
>>
>> http://www.makeuseof.com/tag/quantum-computers-end-cryptography/
>>
>>
>>
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>>
> 
> 
> 
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-- 
***************
Jen
@redshiftzero
PGP 0x90CC0310
@CryptopartyChi
***************

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