I can login to other sites using openid (Including meta.stackoverflow.com)

When I try login to stackoverflow.com, I get this error:

Unable to log in with your OpenID provider:

The signature verification failed.

This happens with both my Google openid, and my launchpad.net openid.

How can I fix this?

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I guess you tried/retry more than a couple of times? –  o.k.w Dec 8 '09 at 10:30
Yes. I also tried clearing my cookies. –  Gary van der Merwe Dec 8 '09 at 10:46
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2 Answers

up vote 3 down vote accepted

Have you tried the troubleshooting steps?


Particularly the link at the bottom:



The fact that it works on test-id.org suggests everything is working. My strongest suspicion then is that something "in between" is somehow corrupting the message before it's read by DNOI and sent back to the OP.

There are only two reasons that DNOI throws this invalid signature exception: its own token signature verification failed or the OP rejected its signature. Since we are using stateless mode, there is no token signature to validate. Leaving either the OP to screw up or to be unable to verify the signature because the message wasn't preserved right because it was modified or changed "in flight" by another entity.

Are you behind a proxy of any kind by chance?

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I can login fine at test-id.org/OP/Sreg.aspx with both my launchpad and google ids. –  Gary van der Merwe Dec 8 '09 at 16:20
Can you try logging into nerdbank.org/RP/login.aspx and reporting back here? –  Andrew Arnott Dec 8 '09 at 16:54
It does seem to be a problem with the net connection, cause I can login else where. –  Gary van der Merwe Jan 10 '10 at 21:12
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Some more details on the very rare Signature Verification Failed error:

From the logs shown, the provider [MyOpenId] has processed several logins from this one person within a very small duration (less than a second). Each authentication received has a nonce in it that can only be used once. As a "dumb-mode" RP, Stack Overflow sends each assertion to myopenid.com for verification, and myopenid.com will (or should) verify the first one, and reject the subsequent ones, if it's actually the same assertion used multiple times, which it likely is.

My only theory to explain what you're seeing is that this person (or his proxy?) is repeating his HTTP request that sends the assertion back to Stack Overflow. And his browser displays the response that came from one any of the tries besides the first one. I don't know why a proxy would do that, but according to the HTTP spec, a GET request is supposed to be entirely benign, which the OpenID spec violates, so I might believe a problem here. One other possible source of the problem would be a browser "accelerator" plugin that aggressively fetches HTTP resources, resulting possibly in multiple calls.

Verifying that this is the problem might be difficult. Certainly you can try using Fiddler on his computer to see if the assertion is sent to Stack Overflow more than once, but that won't capture any funny behavior at the proxy level.

So if you see this in your the OpenID provider logs..

148 ms ago  Approve for http://stackoverflow.com/users/authenticate/
269 ms ago  Approve for http://stackoverflow.com/users/authenticate/
0 min  ago  Approve for http://stackoverflow.com/users/authenticate/

that's bad -- see the multiples, there? And in such a short timeframe?

It should look more like this, one login, one record:

119 ms ago  Approve for http://stackoverflow.com/users/authenticate/
316 ms ago  Sign in by password 

Andrew (resident OpenID expert) noted that some OpenID providers do not validate the time nonces, so you wouldn't necessarily see a problem when using Google or Yahoo. That's why this one is somewhat specific to myopenid and rapid logins.

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Thanks Jeff, whether it's something you've done or the magic healing effects of 'switching it off and on again' I can now log into server fault perfectly :) –  Mark Pim Jan 22 '10 at 10:30
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