[messaging] Do quantum attacks/algos also lead to compromise of PFS?

[Tao Effect]

> As I understand it, quantum computers effectively halve the keyspace, so perhaps "suck" is too strong a term, but it isn't completely catastrophic for symmetric encryption the same way it is with RSA/ECC-like pubkey systems.

That's not my understanding.

The document I'm looking at [1] is quite damning and indicates QM systems break traditional symmetric ciphers like DES and AES in no time at all using "20 questions" algorithm:

> If we guess that each iteration will take 1 millisecond, then the total time for a known plaintext attack on DES is going to be 56 milliseconds.
> 
> Cipher systems like AES-256 can also be broken is less than a second.
> 

- Greg

[1] Quantum Computers for Code Breaking, Dave D' Rave, 2600 Magazine

--
Please do not email me anything that you are not comfortable also sharing with the NSA.

On Jan 25, 2015, at 11:06 AM, Tony Arcieri <bascule at gmail.com> wrote:

> On Sun, Jan 25, 2015 at 11:04 AM, Tao Effect <contact at taoeffect.com> wrote:
> "More good news: quantum computers suck at breaking symmetric encryption"
> 
> Do you have a citation for that? It conflicts with what I've heard from others.
> 
> As I understand it, quantum computers effectively halve the keyspace, so perhaps "suck" is too strong a term, but it isn't completely catastrophic for symmetric encryption the same way it is with RSA/ECC-like pubkey systems.
> 
> --
> Tony Arcieri

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