%% You should probably cite rfc2406 instead of this I-D.
@techreport{ietf-ipsec-esp-v2-05,
    number =    {draft-ietf-ipsec-esp-v2-05},
    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-ipsec-esp-v2/05/},
    author =    {Stephen Kent and Ran Atkinson},
    title =     {{IP Encapsulating Security Payload (ESP)}},
    pagetotal = 22,
    year =      1998,
    month =     may,
    day =       13,
    abstract =  {The Encapsulating Security Payload (ESP) header is designed to provide a mix of security services in IPv4 and IPv6. {[}STANDARDS-TRACK{]}},
}