Ah, sorry, yes I think that's sufficient. I didn't have access to the Internet to double check before I sent the email and I forgot that this was there.<br clear="all">--<br>Andrew Arnott<br>"I [may] not agree with what you have to say, but I'll defend to the death your right to say it." - Voltaire<br>
<br><br><div class="gmail_quote">On Tue, Mar 31, 2009 at 6:24 PM, Allen Tom <span dir="ltr"><<a href="mailto:atom@yahoo-inc.com">atom@yahoo-inc.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div bgcolor="#ffffff" text="#000000">
Hi Andrew,<br>
<br>
Section 10.1 already says:<br>
<br>
openid.response_nonce
<blockquote>
<p> Value: A string 255 characters or less in length, that MUST be
unique to this particular successful authentication response. The nonce
MUST start with the current time on the server, and MAY contain
additional ASCII characters in the range 33-126 inclusive (printable
non-whitespace characters), as necessary to make each response unique.
The date and time MUST be formatted as specified in section 5.6 of <a href="http://openid.net/specs/openid-authentication-2_0.html#RFC3339" target="_blank">[RFC3339]<span>
(</span><span>Klyne, G. and C. Newman, “Date and Time on
the Internet: Timestamps,” .</span><span>)</span></a>, with the
following restrictions: </p>
<ul>
<li> All times must be in the UTC timezone, indicated with a "Z". </li>
<li> No fractional seconds are allowed </li>
</ul>
For example: 2005-05-15T17:11:51ZUNIQUE<br>
<br>
</blockquote>
Is this sufficient?<br><font color="#888888">
<br>
Allen</font><div><div></div><div class="h5"><br>
<br>
<br>
Andrew Arnott wrote:
<blockquote type="cite">Yes, Breno. I'd also like to see the spec give a maximum
allowable length for the nonce to RPs know better what they can expect
and how much storage to allow for nonces.<br clear="all">
--<br>
Andrew Arnott<br>
"I [may] not agree with what you have to say, but I'll defend to the
death your right to say it." - Voltaire<br>
<br>
<br>
<div class="gmail_quote">2009/3/31 Breno de Medeiros <span dir="ltr"><<a href="mailto:breno@google.com" target="_blank">breno@google.com</a>></span><br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><br>
<br>
<div class="gmail_quote">
<div>On Tue, Mar 31, 2009 at 3:46 PM, Martin Atkins <span dir="ltr"><<a href="mailto:mart@degeneration.co.uk" target="_blank">mart@degeneration.co.uk</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
<div>
<div>Andrew Arnott wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
I'm also somewhat curious about how many OpenID consumers actually<br>
do nonce checking. Net::OpenID::Consumer for Perl actually ignores<br>
the nonce altogether and implements its own timestamp checking due<br>
to legacy code for OpenID 1.1, and seems to be vulnerable to replay<br>
for up to 30 seconds after a positive assertion.<br>
<br>
<br>
The author of the Perl library ought to be ashamed. This kind of thing
reduces my confidence in using OpenID at any site other than one that I
wrote the library for myself.<br>
<br>
Although this is what OSIS testing is all about. Hopefully there is a
test to catch RPs and OPs that don't check the nonce for replays.<br>
</blockquote>
<br>
</div>
</div>
Yes. As the maintainer of that library (though not its original
author), I am ashamed, which is what prompted the question in the first
place.</blockquote>
</div>
<div><br>
I believe that the spec should make it clear that the OP is responsible
for validating the uniqueness of the nonce in stateless mode. <br>
</div>
<div>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><br>
<br>
I'd love to have a test in the test suite for this.<br>
<br>
RPs only need to do this checking when they're running in stateful
mode, right? Since stateless RPs have nowhere to store state they can't
retain a history of nonces.<br>
<br>
Can you share some high-level details about your nonce-checking
implementation? Specifically how you persist the previous nonces, when
you expire them, etc?<br>
<br>
I'm wondering if it would instead be simpler to use a client-generated
nonce in the return_to URL, as you note that DotNetOpenID is doing for
1.1 requests, thus allowing the nonce checking to be a whitelist rather
than a blacklist and the nonces to be in a known format that I can
optimize for.
<div>
<div><br>
<br>
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</blockquote>
</div>
</div>
<br>
<br clear="all">
<div>
<div><br>
-- <br>
--Breno<br>
<br>
+1 (650) 214-1007 desk<br>
+1 (408) 212-0135 (Grand Central)<br>
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</blockquote>
</div>
<br>
</blockquote>
<br>
</div></div></div>
</blockquote></div><br>