Responses are in-line. (...) >>>There is a more substantive comment on the first paragraph of >>>section 1. >>> >>>The text states: >>> >>> If an implementation chooses to support one of the algorithms >>> discussed in this document, then the implementation MUST do so as >>> described in this document. >>> >>>I believe the text should be: >>> >>> If an implementation chooses to support one of the algorithms >>> discussed in this document, then the implementation MUST do so as >>> described in [SHS]. >> >>The algorithms aren't defined in this document only the OIDs and where they >>go in CMS ... so I still think it's actually "as described in this >>document". But, Spencer suggests removing the sentences because they're not >>needed and I tend to agree with him. > >Spencer wins on this one. The sentence doesn't make much sense in a >standards-track document. It is important to know in which document the algorithms are described in detail. Deleting the sentence would not solve my concern. >> >A small discussion in the security considerations section on >>>the advantages (in particular in terms of performances versus >>>security) of using one or another function from the SHA2 >>>family would be helpful. >> >>I'll see if I can't get something from NIST (or at least point to it). > >I'll disagree with this. These are not security considerations; they >are performance considerations. And pretty obvious ones at that. It is both performance and security. The larger the hash is, the better is the security, but the performance may be lower. >> >While I welcome this draft, everybody should take into >>>consideration that, if the SHA2 family happens to be broken >>>then we will be at risk. >>>This should be mentioned into the security considerations section. >> >>If an algorithm is cracked then isn't it obvious that we're in trouble? No >>other algorithm document I could find says something like this so I'm >>inclined to not include this in the security considerations section. > >... or anywhere else. If any algorithm (hash, encryption, signing, >...) is broken, it is broken. Sean's right here. The message is the following: if the SHA2 family is broken, then you had better to use two hash algorithms from a different family (e.g. use Whirlpool). We should also reference http://www.ietf.org/internet-drafts/draft-ietf-smime-multisig-04.txt which allows to use two different hash functions (from different families, if possible). Denis _______________________________________________ IETF mailing list IETF@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf