[liberationtech] Quantum computation & communication

[Maxim Kammerer]

On Wed, Dec 19, 2012 at 8:38 AM, Gregory Foster
<gfoster at entersection.org> wrote:
> Aerospace & Defense News (Dec 19) - "Army Researchers Seek Secure Quantum
> Communications":
> http://www.asdnews.com/news-46753/Army_Researchers_Seek_Secure_Quantum_Communications.htm
>
>> "Quantum computers will be able to easily decrypt communications that are
>> currently secure," Meyers said. "We're talking decryption in seconds instead
>> of years. That's one reason why it's vital for us to explore quantum
>> encryption."

I am yet to see evidence that quantum computing is viable for any
non-trivial number of qubits. I think it is more likely that we will
see the idealized notion of quantum superposition break once QC is
pushed far enough, resulting in physics, but not computation
breakthrough, and in ability to still use finite fields-based
cryptography, just with bigger key lengths. Also, as pointed by Matt
Mackall above, there is a frequent misconception that quantum
computers are anything like non-deterministic Turing machines b they
are not, and shuffling-based (i.e., symmetric-key, classical)
cryptography is still resistant to QC, assuming it's actually
resistant to classic computing as well (which is generally seen as a
much stronger assumption than, e.g., assuming that factoring is hard).
Caveat emptor: not my field, inb4 hate from QC people.

-- 
Maxim Kammerer
LibertC) Linux: http://dee.su/liberte
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