%% You should probably cite draft-ietf-core-echo-request-tag instead of this I-D.
@techreport{amsuess-core-repeat-request-tag-00,
    number =    {draft-amsuess-core-repeat-request-tag-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-amsuess-core-repeat-request-tag/00/},
    author =    {Christian Amsüss and John Preuß Mattsson and Göran Selander},
    title =     {{Repeat And Request-Tag}},
    pagetotal = 15,
    year =      2017,
    month =     jul,
    day =       1,
    abstract =  {This document defines two optional extensions to the Constrained Application Protocol (CoAP): the Repeat option and the Request-Tag option. Each of these options when integrity protected, such as with DTLS or OSCOAP, protects against certain attacks on CoAP message exchanges. The Repeat option enables a CoAP server to verify the freshness of a request by requiring the CoAP client to make another request and include a server-provided challenge. The Request-Tag option allows the CoAP server to match message fragments belonging to the same request message, fragmented using the CoAP Block-Wise Transfer mechanism. This document also specifies additional processing requirements on Block1 and Block2 options.},
}