On 12-Oct-24 09:10, Watson Ladd wrote:
Dear all, I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. The summary of the review is Not Ready. The draft does a good job of describing the FNV-1a hash function. However, it falls short on recommending when it should be used and when it should not be. Python had to change away from FNV-1a due to collision attacks leading to DoS (https://peps.python.org/pep-0456/, https://www.youtube.com/watch?v=Vdrab3sB7MU). The offset is insufficient to solve this problem. FNV-1a is slower than other hash functions with better guarantees of equidistribution, taking one multiply per byte and is hard to parallelize. I think this draft needs to say these things, and advise against usage in new applications and protocols.
Isn't that a bit too wide? It took me a while to track it down, but it seems that the original exposition of this problem is at http://events.ccc.de/congress/2011/Fahrplan/attachments/2007_28C3_Effective_DoS_on_web_application_platforms.pdf That seems too narrow an attack to justify avoiding it in *all* new applications and protocols. The whole world is not HTTP POST. I do agree that an additional warning is needed. Brian Carpenter
Sincerely, Watson Ladd
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