<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
tt
{mso-style-priority:99;
font-family:"Courier New";
color:#003366;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><a href="http://openid.net/specs/openid-connect-standard-1_0.html#self_issued.validation">Standard 5.5</a>, list item 5 says:<o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN" style="font-family:"Verdana","sans-serif";color:black">The Client MUST validate that the
</span><tt><span lang="EN" style="font-size:12.0pt">sub</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> (subject) value is the base64url encoded SHA-256 hash of the concatenation of the key values in the
</span><tt><span lang="EN" style="font-size:12.0pt">user_jwk</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> claim. When the
</span><tt><span lang="EN" style="font-size:12.0pt">alg</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> value is
</span><tt><span lang="EN" style="font-size:12.0pt">RS256</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black">, the key values
</span><tt><span lang="EN" style="font-size:12.0pt">mod</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> and
</span><tt><span lang="EN" style="font-size:12.0pt">exp</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> are concatenated in that order. When the
</span><tt><span lang="EN" style="font-size:12.0pt">alg</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> value is
</span><tt><span lang="EN" style="font-size:12.0pt">ES256</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black">, the key values
</span><tt><span lang="EN" style="font-size:12.0pt">crv</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black">,
</span><tt><span lang="EN" style="font-size:12.0pt">x</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> and
</span><tt><span lang="EN" style="font-size:12.0pt">y</span></tt><span lang="EN" style="font-family:"Verdana","sans-serif";color:black"> are concatenated in that order.</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This language leaves it ambiguous whether the concatenated key values in Standard 5.5 supposed to be the base64url encoded values or the raw key bytes? Following the precedents in the JOSE specs, I assume that we would concatenate the
base64url encoded values. Unless I hear objections, I’ll clarify the specs to say that.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> Thanks,<o:p></o:p></p>
<p class="MsoNormal"> -- Mike<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>