[Standards] Privacy lists and the order of items

Jiří Zárevúcký zarevucky.jiri at gmail.com
Tue May 12 07:31:44 UTC 2009


2009/5/12 Remko Tronçon <remko at el-tramo.be>:
> On Mon, May 11, 2009 at 5:51 PM, Dave Cridland <dave at cridland.net> wrote:
>> This did get me wondering about the issue that if there's two semantically
>> identical forms for the same information, then should we ever wish to have
>> clients sign the privacy list, we have a C14N problem.
>
> Well, semantical equivalence  should be checked at the XML level, not
> at the XMPP level. Wouldn't you otherwise have problems with plain
> messages as well, since
> <message><body>a</body><subject>b</subject></message> is equivalent to
> <message><subject>b</subject><body>a</body></message> in XMPP (but not
> in XML).
>
> cheers,
> Remko
>

That's another problem. As Peter pointed out to me earlier, no XMPP
spec ever enforced a particular child order (if the order wouldn't
make a semantic difference in XMPP). If it comes to signing, we can
specify that unordered elements are to be ordered by some algorithm.



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