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0 pointsls6128mo ago0 comments

What is the state of PQ symmetric crypto? My layman's understanding is that 128 bit AES is known to be broken by a quantum computer and that 256 AES may be OK but that isn't certain? Is this an additional vector for the "harvest and wait" strategy in the future?

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5 comments · 2 top-level

dist-epoch8mo ago· 2 in thread

> My layman's understanding is that 128 bit AES is known to be broken by a quantum computer

Weakened, not broken. Quantum computers turns 128 bit AES into 64 bit equivalent. Which will still be extremely difficult for quantum computers due to the large computer size/number of steps required.

SAI_Peregrinus8mo ago

And it's 64-bit equivalent in a way that's inherently impossible to parallelize, so 2^64 sequential quantum operations. Those operations are much, much slower than classical ones.

cyberax8mo ago

You can trivially parallelize Grover's search by assigning each quantum computer it's own search space.

twiggers8mo ago· 1 in thread

128-bit AES is fine. To run Grover’s algorithm against it you’d need to cover the moon with qubits.

ziofill8mo ago

which algorithm are you referring to?

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