[jdev] Case sensitive & jid

Matthias Wimmer m at tthias.net
Sat May 8 02:59:59 CDT 2004


Hi Trejkaz!

Trejkaz Xaoza schrieb am 2004-05-08 10:01:57:
> > Therefore md5(lowercase(jid_full)) would result in
> > the same hash for two different addresses!
> That's actually a property of all hashes anyway.  Comes with the territory of 
> reducing Y bytes to X bytes where X < Y.

No not really. Sure there are always different strings that are mapped
to the same hash. But it's the property of hashes, that it is
hard/impossible to generate a second string that has the same hash on
purpose. (Else you could take a signature of one document and generate a
second document for which this signature is valid too and which tells
that the other person owes you 1,000,000 €.

In the case of md5(lowercase(jid_full)) it would be trivial to generate
two addresses, that are mapped to the same hash.

In case you think that this is "only" possible for resources and one
would only break his own addresses ... nope ... there are components
that allow different users to habe the same node and domain, but a
different resource: e.g. conference servers.


Tot kijk
    Matthias
    
-- 
Fon: +49-(0)70 0770 07770       http://matthias.wimmer.name/
HAM: DB1MW                      xmpp:mawis at charente.de
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