Hi all,

I was wondering if there have been any discussion about new quantum-resistant 
algorithms and their impact on QUIC. Looking back in the list archive I could 
only find 
https://mailarchive.ietf.org/arch/msg/quic/cA_azemZvSQadc9FvWnMfN-malQ/  which 
brought up the initial congestion and the amplification window issues which 
could introduce an RTT each to the handshake due to the large "post-quantum 
auth data" from the server. I don't think that discussion converged to any 
actionable items.

Recently published 
https://www.nccoe.nist.gov/sites/default/files/2023-12/pqc-migration-nist-sp-1800-38c-preliminary-draft.pdf
  (Section 7.3, Figure 5) also showed that packet pacing can introduce >RTT 
time to each handshake. kInitialRtt=333 is a "SHOULD" in RFC9002 so it could be 
adjusted, but I am not sure that should be left to the implementer.

Tweaking the amplification window to 10-15x as the new signature algos would 
require, increases the amplification risk. Validation tokens could alleviate 
the issue especially for clients that keep coming to the same servers, but it 
is not a general solution.

Increasing the initial congestion window is already done by CDNs, but I am not 
sure it is the norm for most QUIC uses.

So, has the WG generally considered options to address these issues?

Thank you,
Panos



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