On 12:33 Fri 13 Mar , Marc Kleine-Budde wrote: > On 03/13/2015 11:05 AM, Jean-Christophe PLAGNIOL-VILLARD wrote: > > On 10:28 Fri 13 Mar , Jan Lübbe wrote: > >> On Do, 2015-03-12 at 19:19 +0100, Jean-Christophe PLAGNIOL-VILLARD wrote: > >>> please do not send a new version except for fix > >>> > >>> I'm going to re-integrate it with the keystore & co > >> > >> Could you describe your keystore design? > > > > I'll send the patch series soon > > > > code is better than 1000s of words > > > > with DER support and the fit > >> > >>> and sha1,rsa2048 is considered weak in term of security > >>> and worse md4/md5 > >>> > >>> for barebox I would only use > >>> at least sha256 with rs2048 or sha512 with rsa4096 > >> > >> Yes, of course. These were only used as an example and it's trivial to > >> switch to other hash algos or RSA key sizes. Also, the FIT format can > >> easily be extended to support ECC/Curve25519. > > > > very slow vs rsa, but as we will use a generic framework we will just need > > to > > add the algo > > > > if you can break rsa4096, the chance you can break ECC are high too > > If you want to open the box, today you would probably not break > rsa2048/sha1 (unless you have huge calculation power) but look for > implementation weaknesses, like bugs or side channel attacks.
I alredy see it done on rsa1024 few years ago, today rs2048 is supposedly secured but as you hw may have to run for 10 years rs2048/sha1 is considered not strong enough Keep in on mind, for security you do need to choose the correct algo for how long the data need to be secured. > > >> In some cases, where the SoC's ROM code only supports RSA2048 with SHA1, > >> using stronger settings in Barebox doesn't increase security. So there > >> we want to use the same settings as the ROM code. > > > > agreed but I refuse to allow it unless we have no choice > > and emit a warning > > > > and even I'll prefer to use stonger, yes this will increase the security. > > As a secure boot is as strong as it's weak link > > > > but this will not reduce it either > > Adding unneeded complexity might not the best move here. common it just change the sha and the number of bits of key Best Regards, J. _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox
