[Standards] Call for Experience: XEP-0203 (Delayed Delivery)

Sergei Golovan sgolovan at gmail.com
Thu Aug 13 09:19:41 UTC 2009

On Thu, Aug 13, 2009 at 1:51 AM, Peter Saint-Andre<stpeter at stpeter.im> wrote:
> 1. Who has implemented XEP-0203? Please note that the protocol must be
> implemented in at least two separate codebases (and preferably more).

Tkabber uses XEP-0203 timestamps as well as XEP-0091 ones (203 is preferrable).

> 2. Have developers experienced any problems with the protocol as defined
> in XEP-0203? If so, please describe the problems and, if possible,
> suggested solutions.

There is oen problem with all current methods of delayed delivery
indication. The problem is that any entity may easily forge message
timestamp. If I send a message with added   <delay
xmlns='urn:xmpp:delay' stamp='2002-09-10T23:08:25Z'/> then my adressee
will believe that this is an offline message which were stored on
server (for several years).

I'm not sure if it's a serious issue, but surely it worth at least
security consideration notice.

As for the solution, I could suggest that any server which routes the
stanza should add a delay timestamp indicating when it reseived the
message (with some additional attribute (e.g. router='jabber.org')
similar to Received header in email. Stripping any delay element from
all stanzas isn't a solution because they are used legitimately in MUC

Sergei Golovan

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