[Mailman-Developers] [Bug 985149] Add List-Post value to permalink hash input

Jeff Breidenbach jeff at jab.org
Tue Apr 24 06:40:35 CEST 2012


I didn't mean to be presmtpuous. I think you are right that user
interfaces can do a good job with crossposts. Here's a great example
from GMane.

   http://mid.gmane.org/20120323220013.0b1c88a8@resist.wooz.org

>32 bytes too long?

Thirty-two characters means 50% likely to have a single collision once
the archival database hits approximately 1.4 septillion messages.

>Is 4 bytes too short?

Four characters is only about a million combinations. First collision
is 50% likely at 1200 messages, and multi-million message databases
are completely screwed.

Bottom line: how big a database do we expect to have, and amongst
those messages, how many collisions are considered acceptable?

-Jeff

PS. These numbers assume a well balanced hash. This paper suggests
SHA-1 is pretty good in non-adversarial situations, but I'm not an
expert.  http://cseweb.ucsd.edu/~mihir/papers/balance.html


More information about the Mailman-Developers mailing list