%% You should probably cite draft-ietf-sipping-certs instead of this I-D.
@techreport{jennings-sipping-certs-04,
    number =    {draft-jennings-sipping-certs-04},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-jennings-sipping-certs/04/},
    author =    {Cullen Fluffy Jennings and Jon Peterson},
    title =     {{Certificate Management Service for SIP}},
    pagetotal = 17,
    year =      2004,
    month =     jul,
    day =       21,
    abstract =  {This draft defines a Credential Service that uses a SIP subscribe/ notify mechanism to discover other users' certificates and credentials and be notified about changes to these certificates. Other user agents that want to contact that AOR can retrieve these certificates from the server. The result is that widespread deployment of S/MIME in SIP is possible, because no extra expense or effort is required of the end user. This work is being discussed on the sipping@ietf.org mailing list.},
}