<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=Windows-1252">
</head>
<body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">
<blockquote type="cite">
<div bgcolor="#FFFFFF" text="#000000"><font face="Helvetica, Arial, sans-serif">I don't know where the best place is to provide this guidance. If we have a "validating the ID Token" sub-section in the new ID Token section, then maybe it would best fit there.<br>
</font></div>
</blockquote>
<div><br>
</div>
<div>+1 to this idea with a cross link from the nonce definition.</div>
<div><br>
</div>
<div> -- Justin</div>
<div><br>
</div>
<br>
<div>
<div>On Oct 25, 2013, at 6:17 AM, George Fletcher <<a href="mailto:gffletch@aol.com">gffletch@aol.com</a>> wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div bgcolor="#FFFFFF" text="#000000"><font face="Helvetica, Arial, sans-serif">If we are going to give guidance, then we really need to give guidance for two different use cases...<br>
<br>
1. The "client" will validate the response locally in the browser<br>
2. The "client" will validate the response at it's server (even though it's using the implicit flow)<br>
<br>
For use case 1: One method to achieve this is for the client to generate a random string with sufficient entropy and store a SHA-1 hash of the string in local storage. Then use the SHA-1 hash of the random string as the value of the nonce parameter. To validate
the nonce on receipt of the ID Token, extract the nonce from the ID Token and compare it to the stored SHA-1 hash in local storage.<br>
<br>
For use case 2: One method to achieve this is for the backend server to use a SHA-1 hash of the "clients" protected session cookie as the value of the nonce parameter when constructing the AuthorizationRequest. Note that the Session cookie SHOULD be protected
(restricted to SSL and not readable by JavaScript) for this method. To validate the ID Token at the server, the server calculates a SHA-1 hash of the Session cookie value and compares that to the nonce value in the ID Token.<br>
<br>
I don't know where the best place is to provide this guidance. If we have a "validating the ID Token" sub-section in the new ID Token section, then maybe it would best fit there.<br>
<br>
Thanks,<br>
George<br>
<br>
</font>
<div class="moz-cite-prefix">On 10/24/13 7:16 PM, John Bradley wrote:<br>
</div>
<blockquote cite="mid:9FFAFB68-6C38-49B3-B1B7-4EC201A8340E@ve7jtb.com" type="cite">
<base href="x-msg://19/">We want the implicit flow to validate nonce, it would be better to have some reasonable advice for using HTML local storage rather than session cookies.
<div><br>
<div>
<div>On 2013-10-24, at 3:44 PM, Mike Jones <<a moz-do-not-send="true" href="mailto:Michael.Jones@microsoft.com">Michael.Jones@microsoft.com</a>> wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div link="blue" vlink="purple" style="font-family:
Helvetica; font-size: medium; font-style: normal;
font-variant: normal; font-weight: normal; letter-spacing:
normal; line-height: normal; orphans: 2; text-align:
-webkit-auto; text-indent: 0px; text-transform: none;
white-space: normal; widows: 2; word-spacing: 0px;
-webkit-text-size-adjust: auto; -webkit-text-stroke-width:
0px; " lang="EN-US">
<div class="WordSection1" style="page: WordSection1; ">
<div style="margin: 0in 0in 0.0001pt; font-size: 12pt;
font-family: 'Times New Roman', serif; ">
<span style="font-size: 11pt; font-family: Calibri,
sans-serif; color: rgb(31, 73, 125); ">We could drop it from the Implicit Flow, as it’s already present in the Code Flow. Does that work for people?<o:p></o:p></span></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 12pt;
font-family: 'Times New Roman', serif; ">
<span style="font-size: 11pt; font-family: Calibri,
sans-serif; color: rgb(31, 73, 125); "> </span></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 12pt;
font-family: 'Times New Roman', serif; ">
<span style="font-size: 11pt; font-family: Calibri,
sans-serif; color: rgb(31, 73, 125); "> -- Mike<o:p></o:p></span></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 12pt;
font-family: 'Times New Roman', serif; ">
<span style="font-size: 11pt; font-family: Calibri,
sans-serif; color: rgb(31, 73, 125); "> </span></div>
<div>
<div style="border-style: solid none none;
border-top-width: 1pt; border-top-color: rgb(181,
196, 223); padding: 3pt 0in 0in; ">
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
<b><span style="font-size: 10pt; font-family: Tahoma,
sans-serif; ">From:</span></b><span style="font-size: 10pt; font-family: Tahoma,
sans-serif; "><span class="Apple-converted-space"> </span>Richer, Justin
P. [<a class="moz-txt-link-freetext" href="mailto:jricher@">mailto:jricher@</a><a moz-do-not-send="true" href="http://mitre.org/">mitre.org</a>]<span class="Apple-converted-space"> </span><br>
<b>Sent:</b><span class="Apple-converted-space"> </span>Thursday, October 24, 2013 12:56 PM<br>
<b>To:</b><span class="Apple-converted-space"> </span>Mike Jones<br>
<b>Cc:</b><span class="Apple-converted-space"> </span><a moz-do-not-send="true" href="mailto:openid-specs-ab@lists.openid.net">openid-specs-ab@lists.openid.net</a><br>
<b>Subject:</b><span class="Apple-converted-space"> </span>Re: [Openid-specs-ab] Nonce value suggestion for the Implicit Flow<o:p></o:p></span></div>
</div>
</div>
<div style="margin: 0in 0in 0.0001pt; font-size: 12pt;
font-family: 'Times New Roman', serif; ">
<o:p> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 12pt;
font-family: 'Times New Roman', serif; ">
I'm actually in favor of dropping this example, or else providing it in a list of alternatives. The important thing is that the client can validate the exact value of the nonce parameter on its way back through, the mechanics of how that happens are client
specific (but we can provide simple guidance).<o:p></o:p></div>
<div>
<div style="margin: 0in 0in 0.0001pt; font-size: 12pt;
font-family: 'Times New Roman', serif; ">
<o:p> </o:p></div>
<div>
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
-- Justin<o:p></o:p></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
<o:p> </o:p></div>
<div>
<div>
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
On Oct 24, 2013, at 11:44 AM, Mike Jones <<a moz-do-not-send="true" href="mailto:Michael.Jones@microsoft.com" style="color: purple; text-decoration:
underline; ">Michael.Jones@microsoft.com</a>><o:p></o:p></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
wrote:<o:p></o:p></div>
</div>
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
<br>
<br>
<o:p></o:p></div>
<div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; ">For the Implicit Flow, the “nonce” description contains this text at<a moz-do-not-send="true" href="http://openid.bitbucket.org/openid-connect-core-1_0.html#ImplicitAuthorizationRequest" style="color: purple; text-decoration:
underline; "><span style="color: purple;
">http://openid.bitbucket.org/openid-connect-core-1_0.html#ImplicitAuthorizationRequest</span></a>:<o:p></o:p></span></div>
</div>
<div style="margin-left: 0.5in; ">
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Verdana, sans-serif; " lang="EN">Sufficient entropy MUST be present in the<span class="apple-converted-space"> </span></span><tt style="font-family: 'Courier New'; "><span style="color: rgb(0, 51, 102); " lang="EN">nonce</span></tt><span class="apple-converted-space"><span style="font-size: 11pt; font-family:
Verdana, sans-serif; " lang="EN"> </span></span><span style="font-size: 11pt; font-family:
Verdana, sans-serif; " lang="EN">values
used to prevent attackers from guessing values.<span class="apple-converted-space"> </span><span style="background-color: yellow;
background-position: initial initial;
background-repeat: initial initial; ">One
method to achieve this is to store a random value as a signed session cookie, and pass the value in the</span></span><tt style="font-family: 'Courier New'; "><span style="color: rgb(0, 51, 102);
background-color: yellow;
background-position: initial initial;
background-repeat: initial initial; " lang="EN">nonce</span></tt><span class="apple-converted-space"><span style="font-size: 11pt; font-family:
Verdana, sans-serif; background-color:
yellow; background-position: initial
initial; background-repeat: initial
initial; " lang="EN"> </span></span><span style="font-size: 11pt; font-family:
Verdana, sans-serif; background-color:
yellow; background-position: initial
initial; background-repeat: initial
initial; " lang="EN">parameter.
In that case, the<span class="apple-converted-space"> </span></span><tt style="font-family: 'Courier New'; "><span style="color: rgb(0, 51, 102);
background-color: yellow;
background-position: initial initial;
background-repeat: initial initial; " lang="EN">nonce</span></tt><span class="apple-converted-space"><span style="font-size: 11pt; font-family:
Verdana, sans-serif; background-color:
yellow; background-position: initial
initial; background-repeat: initial
initial; " lang="EN"> </span></span><span style="font-size: 11pt; font-family:
Verdana, sans-serif; background-color:
yellow; background-position: initial
initial; background-repeat: initial
initial; " lang="EN">in
the returned ID Token can be compared to the signed session cookie to detect ID Token replay by third parties.</span><span style="font-size: 11pt; font-family:
Calibri, sans-serif; "><o:p></o:p></span></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; "> <o:p></o:p></span></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; ">George wrote this about the suggestion in his review:<o:p></o:p></span></div>
</div>
<div style="margin-left: 0.5in; ">
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; ">“I'm not sure this suggestion makes sense for the implicit flow. The client would need to write a cookie value on the domain of the redirect_uri and the attempt
to read it on the return of the implicit flow. Wondering if a local storage example would make more sense.”<o:p></o:p></span></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; "> <o:p></o:p></span></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; ">Do people agree with him? If so, does someone want to supply specific alternative text to use?<o:p></o:p></span></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; "> <o:p></o:p></span></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; "> -- Mike<o:p></o:p></span></div>
</div>
<div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 12pt; font-family: 'Times New
Roman', serif; ">
<span style="font-size:
11pt; font-family: Calibri, sans-serif; "> <o:p></o:p></span></div>
</div>
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
<span style="font-size: 13.5pt; font-family:
Helvetica, sans-serif; ">_______________________________________________<br>
Openid-specs-ab mailing list<br>
<a moz-do-not-send="true" href="mailto:Openid-specs-ab@lists.openid.net" style="color: purple; text-decoration:
underline; "><span style="color: purple; ">Openid-specs-ab@lists.openid.net</span></a><br>
<a moz-do-not-send="true" href="http://lists.openid.net/mailman/listinfo/openid-specs-ab" style="color: purple; text-decoration:
underline; "><span style="color: purple; ">http://lists.openid.net/mailman/listinfo/openid-specs-ab</span></a><o:p></o:p></span></div>
</div>
</div>
<div style="margin: 0in 0in 0.0001pt; font-size:
12pt; font-family: 'Times New Roman', serif; ">
<o:p> </o:p></div>
</div>
</div>
</div>
_______________________________________________<br>
Openid-specs-ab mailing list<br>
<a moz-do-not-send="true" href="mailto:Openid-specs-ab@lists.openid.net">Openid-specs-ab@lists.openid.net</a><br>
<a class="moz-txt-link-freetext" href="http://lists.openid.net/mailman/listinfo/openid-specs-ab">http://lists.openid.net/mailman/listinfo/openid-specs-ab</a></div>
</blockquote>
</div>
<br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset> <br>
<pre wrap="">_______________________________________________
Openid-specs-ab mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Openid-specs-ab@lists.openid.net">Openid-specs-ab@lists.openid.net</a>
<a class="moz-txt-link-freetext" href="http://lists.openid.net/mailman/listinfo/openid-specs-ab">http://lists.openid.net/mailman/listinfo/openid-specs-ab</a>
</pre>
</blockquote>
<br>
<div class="moz-signature">-- <br>
<a href="http://connect.me/gffletch" title="View full card on
Connect.Me"><span><XeC.png></span></a></div>
</div>
_______________________________________________<br>
Openid-specs-ab mailing list<br>
<a href="mailto:Openid-specs-ab@lists.openid.net">Openid-specs-ab@lists.openid.net</a><br>
http://lists.openid.net/mailman/listinfo/openid-specs-ab<br>
</blockquote>
</div>
<br>
</body>
</html>