Re: [cryptography] Do quantum attacks/algos also lead to compromise of PFS?

2015-01-24 Thread Natanael
Den 24 jan 2015 22:06 skrev Greg g...@kinostudios.com:

 So, I understand that QM algos can pretty much dismantle all popular
asymmetric encryption algos with enough q-bits, but I haven't thought hard
enough to see if they also can be used to compromise communications that
used DH to do PFS underneath the initial handshake.

 Side question: is this the right list to ask this on, or is there other
ones I should try? (Is CFRG appropriate? Metzdowd is annoying with its long
moderation times...)

Key exchange like DH simplifies PFS but isn't strictly necessary. A
mechanism with temporary public keys where your main keys only sign the
temporary keys, and the temporary keys are used for exchange of nonces to
generate session keys (there are presumed quantum secure public key
algorithms!), would be sufficient as well if you delete the temporary
public keys the way DH secrets in regular PFS key exchanges are deleted
afterwards.

There are many hash based signature algorithms, and other types of public
key algorithms like lattice based and many others.
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Re: [cryptography] Do quantum attacks/algos also lead to compromise of PFS?

2015-01-24 Thread Greg
Thanks Natanael!

What I'm gathering from here and [messaging] is that yes, OTR doesn't seem seem 
to be future-secure, and PFS isn't perfect (with the way it's usually 
implemented today), *but* there do seem to be possible solutions to this 
problem, if we can trust what the math/physics folks are saying.

-g

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On Jan 24, 2015, at 1:13 PM, Natanael natanae...@gmail.com wrote:

 
 Den 24 jan 2015 22:06 skrev Greg g...@kinostudios.com:
 
  So, I understand that QM algos can pretty much dismantle all popular 
  asymmetric encryption algos with enough q-bits, but I haven't thought hard 
  enough to see if they also can be used to compromise communications that 
  used DH to do PFS underneath the initial handshake.
 
  Side question: is this the right list to ask this on, or is there other 
  ones I should try? (Is CFRG appropriate? Metzdowd is annoying with its long 
  moderation times...)
 
 Key exchange like DH simplifies PFS but isn't strictly necessary. A mechanism 
 with temporary public keys where your main keys only sign the temporary keys, 
 and the temporary keys are used for exchange of nonces to generate session 
 keys (there are presumed quantum secure public key algorithms!), would be 
 sufficient as well if you delete the temporary public keys the way DH secrets 
 in regular PFS key exchanges are deleted afterwards.
 
 There are many hash based signature algorithms, and other types of public key 
 algorithms like lattice based and many others.
 



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Re: [cryptography] Do quantum attacks/algos also lead to compromise of PFS?

2015-01-24 Thread Kevin

On 1/24/2015 3:56 PM, Greg wrote:
So, I understand that QM algos can pretty much dismantle all popular 
asymmetric encryption algos with enough q-bits, but I haven't thought 
hard enough to see if they also can be used to compromise 
communications that used DH to do PFS underneath the initial handshake.


Side question: is this the right list to ask this on, or is there 
other ones I should try? (Is CFRG appropriate? Metzdowd is annoying 
with its long moderation times...)


Thanks,
Greg

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sharing with the NSA.




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I believe Grover's algorithm is the quickist at doing what you are 
talking about.



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Kevin



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