Yes, DotNetOpenAuth RPs attach their own nonces to their return_to's when communicating with 1.0 OPs<http://blog.nerdbank.net/2009/03/replay-protection-for-openid-1x-relying.html>. It would be a simple matter to expand the scenarios it activates this behavior for if necessary. -- Andrew Arnott "I [may] not agree with what you have to say, but I'll defend to the death your right to say it." - S. G. Tallentyre
On Mon, Jun 8, 2009 at 4:47 PM, John Bradley <[email protected]> wrote: > The other approach that has been used to secure 1.1 RP's is to place a > signed nonce in the nonce in the return_to URI. The RP verifies its own > sig. > I believe this is an option in DotNetOpenAuth for openID as well. > > This removes the need for the RP to synchronize data across servers. This > assumes properly configured load balancers though. > > That is one other approach. > > John B. > On 8-Jun-09, at 7:35 PM, Allen Tom wrote: > > Hi Johannes, > > My personal opinion is that if HTTPS is used for the entire protocol flow, > including the RP's return_to URL, then the RP should be able to verify that > the timetamp in the nonce is current, to within a few minutes, as opposed to > having to verify that the entire nonce is truly unique. > > Allen > > > > Johannes Ernst wrote: > > > On Jun 8, 2009, at 15:50, Allen Tom wrote: > > 6) Pull the replay warning into its own bullet, and mention the use of a > timestamp to bound the time nonces must be stored for. > > [atom] Also a good point. On a related note, many large globally > distributed RPs may have a hard time implementing nonces as per the OpenID > spec, as it's technically tricky to globally replicate data, especially if > it needs to be replicated very quickly. In practice, RPs may only find it > practical to verify that the timestamp is "current" as opposed to actually > verifying that the nonce is can only be used once. > > > In this case, do these mythical "globally distributed RPs" have a better > approach for avoiding replay attacks or do they simply swallow that risk > because no better approach is known. > > Just wondering ... > > > > > > Johannes Ernst > NetMesh Inc. > > > ------------------------------ > > <mime-attachment.gif> > > > > ------------------------------ > > <mime-attachment.gif> > > http://netmesh.info/jernst > > > > > _______________________________________________ > security mailing list > [email protected] > http://openid.net/mailman/listinfo/security > > >
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