Re: [TLS] concers about draft-balfanz-tls-obc

[Yoav Nir <[e-mail]>]

On Nov 18, 2011, at 11:34 PM, Nico Williams wrote:
>>    2. If client authentication is not required, then there is neither need
>> to send a self-signed certificate.
> 
> Client authentication is orthogonal to OBC.
> 
> OBC protects the session cookies from theft.  Let's say you steal my
> session cookies somehow (e.g., via the BEAST attack): but if you don't
> have my OBCs' private keys then you can't actually make use of my
> cookies.
> 
> With OBC cookie theft is not enough.  With OBC the attacker must get
> at the private keys for the OBCs.
> 
> Also, with OBC you get closer to true logout: destroy ("forget") your
> OBC private keys and your sessions are as good as dead.  Moreover, the
> user-agent, not the server, is in control of maximum session lifetime,
> since there's no point in the server setting cookies that will outlive
> the OBCs. 

I we can find no other use case, we might want to rename it to "Origin Bound Cookie".

But that would require some interesting interaction between layers. 

Are all cookies received while using OBC considered (by the client!) bound to the OBC? If not, the client might use an old cookie after a logout event, leading to the server falsely detecting an attempt to forge a cookie. Maybe we need a new keyword on the cookie header.

Where is the "logout" button?  If it's part of the website (in the "canvas") how does the HTML/HTTP tell the browser to log out? Probably best to have it in the Chrome for sites where OBC are supported.