Re:The Day When Computers Can Break All Encryption Is Coming
by mrob on Sunday June 09, 2019 @08:33AM
(#20138776)
The best known quantum attack against symmetric ciphers uses Grover's algorithm to effectively halve the key size. AES-128 is considered secure against classical attacks, so assuming you have a secure side channel for key distribution, AES-256 is sufficient to defeat quantum attacks.
Re:The Day When Computers Can Break All Encryption Is Coming
by nabla9 on Sunday June 09, 2019 @08:46AM
(#20138823)
I assume that we are talking about situations where public key cryptography is used.
If you share one master key for long time, having (effectively) 128-bit secret shared state is too small.
Using side channel to share single 512-bit key that is used to generate other keys keys is enough.