@misc{rfc9470,
    series =    {Request for Comments},
    number =    9470,
    howpublished =  {RFC 9470},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC9470},
    url =       {https://www.rfc-editor.org/info/rfc9470},
    author =    {Vittorio Bertocci and Brian Campbell},
    title =     {{OAuth 2.0 Step Up Authentication Challenge Protocol}},
    pagetotal = 14,
    year =      2023,
    month =     sep,
    abstract =  {It is not uncommon for resource servers to require different authentication strengths or recentness according to the characteristics of a request. This document introduces a mechanism that resource servers can use to signal to a client that the authentication event associated with the access token of the current request does not meet its authentication requirements and, further, how to meet them. This document also codifies a mechanism for a client to request that an authorization server achieve a specific authentication strength or recentness when processing an authorization request.},
}