%% You should probably cite rfc8439 instead of this I-D.
@techreport{nir-cfrg-rfc7539bis-04,
    number =    {draft-nir-cfrg-rfc7539bis-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-nir-cfrg-rfc7539bis/04/},
    author =    {Yoav Nir and Adam Langley},
    title =     {{ChaCha20 and Poly1305 for IETF Protocols}},
    pagetotal = 46,
    year =      2018,
    month =     mar,
    day =       29,
    abstract =  {This document defines the ChaCha20 stream cipher as well as the use of the Poly1305 authenticator, both as stand-alone algorithms and as a "combined mode", or Authenticated Encryption with Associated Data (AEAD) algorithm. RFC 7539, the predecessor of this document, was meant to serve as a stable reference and an implementation guide. It was a product of the Crypto Forum Research Group (CFRG). This document merges the errata filed against RFC 7539 and adds a little text to the Security Considerations section.},
}