%% You should probably cite rfc8162 instead of this I-D.
@techreport{ietf-dane-smime-08,
    number =    {draft-ietf-dane-smime-08},
    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-dane-smime/08/},
    author =    {Paul E. Hoffman and Jakob Schlyter},
    title =     {{Using Secure DNS to Associate Certificates with Domain Names For S/MIME}},
    pagetotal = 7,
    year =      2015,
    month =     feb,
    day =       20,
    abstract =  {This document describes how to use secure DNS to associate an S/MIME user's certificate with the intended domain name, similar to the way that DANE (RFC 6698) does for TLS.},
}