Channel-Bound Cookies

[dentarg]

http://www.browserauth.net/channel-bound-cookies

We call an HTTP connection over TLS an HTTPS channel. When such an HTTPS channel uses Token Binding, the server can bind its cookies to the HTTPS channel by associating them with the client's public Token Binding key, and ensuring that the cookies are only ever used over HTTPS channels authenticated with that public (client) key.

This means that if such a channel-bound cookie is ever stolen off a client's machine, that cookie won't be able to authenticate an HTTP session to the server from other machines. This includes man-in-the-middle attackers that inject themselves into the connection between client and server, perhaps by tricking users into clicking through certificate-mismatch warnings: such a man-in-the-middle will have to generate its own HTTPS channel with the server, which won't match the channel that the cookie is bound it.

See also https://www.google.com/chrome/browser/privacy/whitepaper.html#tls