[Standards] hash agility in file transfer

Dave Cridland dave at cridland.net
Thu Jun 16 08:02:54 UTC 2011

On Thu Jun 16 08:58:27 2011, Remko Tronçon wrote:
> I think 99% will want to say 1, but I think we have to go with 2 in
> case someone doesn't. Ash I think that supporting 2 is enough, no?  
> (1
> would only be convenience, but it's easy enough to programatically  
> add
> all hashes you support for every feature that supports hashes?)
True - (1) is a way of forcing implementors to unify their hashing,  
and it's probably not required.

> And as element names: the IANA hash names are all upper case, right?
> Can we get by by agreeing we use the lowercase version of the IANA
> names as element names?

They're lowercase.

The usual way that IANA names differ from other names is that IANA  
always hash the hyphen in SHA names, hence "sha-1" instead of "sha1".  
Generally, most protocols treat them as case insensitive, I believe,  
hence "SHA-1" == "sha-1", but I don't think we have that option with  
URN forms.

(We do, of course, with simple attributes, but the risk there is that  
we would have different comparisons in different cases, and therefore  

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