%% You should probably cite rfc3851 instead of this I-D.
@techreport{ietf-smime-rfc2633bis-09,
    number =    {draft-ietf-smime-rfc2633bis-09},
    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-smime-rfc2633bis/09/},
    author =    {Blake C. Ramsdell},
    title =     {{Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Message Specification}},
    pagetotal = 36,
    year =      2004,
    month =     apr,
    day =       19,
    abstract =  {This document defines Secure/Multipurpose Internet Mail Extensions (S/MIME) version 3.1. S/MIME provides a consistent way to send and receive secure MIME data. Digital signatures provide authentication, message integrity, and non-repudiation with proof of origin. Encryption provides data confidentiality. Compression can be used to reduce data size. This document obsoletes RFC 2633. {[}STANDARDS-TRACK{]}},
}