@techreport{irtf-asrg-cri-00,
    number =    {draft-irtf-asrg-cri-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-irtf-asrg-cri/00/},
    author =    {Eric Dean and Yakov Shafranovich},
    title =     {{Challenge / Response Interworking (CRI) Framework for Challenge / Response Email Systems}},
    pagetotal = 0,
    year =      2003,
    month =     sep,
    day =       23,
    abstract =  {SMTP was designed simply to deliver email messages without authenticating sources or senders of email messages. In an affort to reduce spam on the Internet, Challenge/Response ('C/R') email systems were developed to provide a method for validating message origination for an intended recipient. This document defines a Challenge / Response Interworking ('CRI') protocol by proposing the use of SMTP extensions and MIME headers for interoperability of C/R systems. This document also defines a set of guidelines for continued use with existing non-CRI mail systems and clients.},
}