On Tuesday 13 January 2009 15:47:22 Paul Hoffman wrote: > At 3:31 PM +0000 1/13/09, Rob Stradling wrote: > >Why "almost every piece of PKIX validating software" ? > > > >I think it would be worth it if, at a minimum... > > - the majority of CAs added the extension to the certificates they > > issue, and... > > - Mozilla implemented support for the extension in NSS. > > > >This would allow Mozilla to disable a weak algorithm quickly, without > > having to wait for the majority of certificates in the wild to stop using > > that algorithm for their main certificate signature. > > Fair enough. > > >I think the biggest barrier to adoption would be convincing enough of the > > CAs to implement it. > > Really? :-) > > >But perhaps the Mozilla CA Certificate Policy could be > >updated to require CAs to implement it? > > That seems kind of drastic for an extension that would only help on a > security issue that has never been met
True. > That is, the extension will only be useful for hash functions for which > practical pre-image attacks are discovered, or signature functions that > quickly become drastically weaker than expected. It's like an insurance policy. CAs and PKIX validating software would pay a premium (i.e. development effort required to support the proposed certificate extension), but would hope that they never need to "make a claim". > I still think it is sufficient for the policy to list the acceptable signing > algorithms of the day. If the extension is standardized and is used > by any CAs, and if NSS implements it and allows Firefox to be able to shut > off one of multiple algorithms in the extension, that would help the CAs > who used the extension. "if NSS implements it". To the NSS developers: If there existed a standardized certificate extension in which a CA could put additional signatures using different algorithms, do you think you'd consider adding support for it to NSS? If yes, might you do this before it was widely supported by CAs, or do you think you'd wait for the majority of CAs to start using it first? -- Rob Stradling Senior Research & Development Scientist Comodo - Creating Trust Online Office Tel: +44.(0)1274.730505 Fax Europe: +44.(0)1274.730909 www.comodo.com Comodo CA Limited, Registered in England No. 04058690 Registered Office: 3rd Floor, 26 Office Village, Exchange Quay, Trafford Road, Salford, Manchester M5 3EQ This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the sender by replying to the e-mail containing this attachment. Replies to this email may be monitored by Comodo for operational or business reasons. Whilst every endeavour is taken to ensure that e-mails are free from viruses, no liability can be accepted and the recipient is requested to use their own virus checking software. _______________________________________________ dev-tech-crypto mailing list dev-tech-crypto@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-tech-crypto
