%% You should probably cite rfc6664 instead of this I-D.
@techreport{ietf-pkix-pubkey-caps-04,
    number =    {draft-ietf-pkix-pubkey-caps-04},
    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-pkix-pubkey-caps/04/},
    author =    {Jim Schaad},
    title =     {{S/MIME Capabilities for Public Key Definitions}},
    pagetotal = 23,
    year =      2011,
    month =     nov,
    day =       15,
    abstract =  {This document defines a set of S/MIME Capability types for ASN.1 encoding for the current set of public keys define in the PKIX working group. This facilitates the ability for a requester to specify information on the public keys and signature algorithms to be used in responses. An example of where this is used is with the OCSP Agility draft.},
}