[Unbearable] More thoughts on reverse-proxies

[Bill Cox <[e-mail]>]

I like the TTRP spec, but there are at least two other modes of operation a
reverse proxy might want to use.

The simplest way for an organization that uses NGINX to enable token
binding is to use Piotr's token-binding module
<https://github.com/google/ngx_token_binding>.  Piotr did great work on
that, but there is room for improvement, such as using a more modern and
shorter MAC appended to the cookie.  Would it make sense to have an RFC for
this mode of operation?  That way, javascript that manipulates the cookie
cleartext would be simpler to write: it would only have to look for one
token-bound cookie format.

The other mode of operation is one I favor for large scale deployments: The
proxy could compute the EKG value needed for verification and pass this in
a new header to the back-end.  Then, the cookie server could verify cookie
TB signatures in the back-end.  This scheme has several advantages: