%% You should probably cite draft-ietf-sipcore-sec-flows instead of this I-D.
@techreport{ietf-sip-sec-flows-01,
    number =    {draft-ietf-sip-sec-flows-01},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-sip-sec-flows/01/},
    author =    {Cullen Fluffy Jennings},
    title =     {{Example call flows using Session Initiation Protocol (SIP) security mechanisms}},
    pagetotal = 45,
    year =      2006,
    month =     jun,
    day =       27,
    abstract =  {This document shows example call flows demonstrating the use of Transport Layer Security (TLS), and Secure/Multipurpose Internet Mail Extensions (S/MIME) in Session Initiation Protocol (SIP). It also provides information that helps implementers build interoperable SIP software. To help facilitate interoperability testing, it includes certificates used in the example call flows and processes to create certificates for testing.},
}