%% You should probably cite rfc2841 instead of this I-D.
@techreport{simpson-ah-sha-kdp-00,
    number =    {draft-simpson-ah-sha-kdp-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-simpson-ah-sha-kdp/00/},
    author =    {William A. Simpson and Perry E. Metzger},
    title =     {{IP Authentication using Keyed SHA1 with Interleaved Padding (IP-MAC)}},
    pagetotal = 9,
    year =      1996,
    month =     may,
    day =       1,
    abstract =  {This document describes the use of keyed SHA1 (Secure Hash Algorithm) with the IP Authentication Header. This memo defines a Historic Document for the Internet community.},
}