On 28/06/13 09:34, Thijs Kinkhorst wrote: > On Thu, June 27, 2013 22:16, Daniel Pocock wrote: >> On 27/06/13 21:44, Florian Weimer wrote: >>> * Daniel Pocock: >>> >>>> However, are such issues at the discretion of package maintainers and >>>> upstream, or is it useful to have a uniform Debian approach to >>>> cryptographic strength? >>> >>> Keep in mind that RFC 4880 (OpenPGP) hard-codes SHA-1 in several >>> places, notably for key fingerprints. If there's a uniform strength >>> requirement, we need some weasel words that GnuPG remains compliant. >>> >>> It's also unclear if SHA-256 or SHA-512 is stronger, and if either >>> really is that much better than SHA-1. >> >> Just to clarify, although my query was related to the use of this hash >> in GnuPG, the reason for the email on debian-devel is for the >> system-wide policy on hashes: which could mean any package (e.g. git >> uses SHA-1 too, some of the X.509 root certs use an SHA-1 hash) >> >> The first question then - do we even need to care, as a project, about >> being pro-active? Or just leave it at the discretion of derivatives and >> end-users to make their own policies? That's quite OK as long as this >> approach is documented. The security page[1] says "Debian takes >> security very seriously" and some users may ask how we apply that >> philosophy to SHA-1 given that it is on various alerts[2]. >> >> It may be that we say "Some packages include SHA-1 technology and if the >> attack potential crosses some threshold X the security team will not >> support them." Then it is up to maintainers and upstreams to think >> about and start making plans for the future of their packages. > > I think such decisions are indeed best left to individual package > maintainers as there's in my opinion no one sound advice that works for > all cases. While moving away from SHA-1 right now might make sense in some > cases, in others it's still problematic. You name X.509: CA roots are by > and large not moving away from SHA-1; you name GnuPG: SHA-1 is indeed in > the standard and signing stuff with non-SHA-1 hashes still leads to > compatibility issues which make that there's a good case for keeping the > current default.
Just out of interest, a CA can re-issue their root cert with the same key pair but a stronger hash. This type of thing has happened before. > Although deprecation is good, there's also still doubt on where to migrate > to. Per-package decisions are hence a much more suited approach than > archive-wide policies. > I agree it is not clear - if there was a clear bug and a clear solution I would have just filed a bug report. As it stands, I will probably start a wiki on crypto-strength issues to start gathering information that is relevant. Then users and maintainers will have something to refer to when such issues come up in future. -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/51cdfb24.7030...@pocock.com.au
