Token Binding over HTTP
RFC 8473

Approval announcement
Draft of message to be sent after approval:

From: The IESG <>
To: IETF-Announce <>
Cc: The IESG <>,, John Bradley <>,,,,,
Subject: Protocol Action: 'Token Binding over HTTP' to Proposed Standard (draft-ietf-tokbind-https-18.txt)

The IESG has approved the following document:
- 'Token Binding over HTTP'
  (draft-ietf-tokbind-https-18.txt) as Proposed Standard

This document is the product of the Token Binding Working Group.

The IESG contact persons are Benjamin Kaduk and Eric Rescorla.

A URL of this Internet Draft is:

Technical Summary

  This document describes a collection of mechanisms that allow HTTP
  servers to cryptographically bind security tokens (such as cookies
  and OAuth tokens) to TLS connections.

  We describe both first-party and federated scenarios.  In a first-
  party scenario, an HTTP server is able to cryptographically bind the
  security tokens it issues to a client, and which the client
  subsequently returns to the server, to the TLS connection between the
  client and server.  Such bound security tokens are protected from
  misuse since the server can generally detect if they are replayed
  inappropriately, e.g., over other TLS connections.

  Federated token bindings, on the other hand, allow servers to
  cryptographically bind security tokens to a TLS connection that the
  client has with a different server than the one issuing the token.

  This Internet-Draft is a companion document to The Token Binding

Working Group Summary
 This document achieved WG consensus and had no objections.

Document Quality

Multiple Implementations of Token Binding exist and have undergone informal interoperability testing.
Google has token binding behind a feature flag in Chrome that is currently defaulted off.  They have also implemented it in their reverse proxy infrastructure. They have also added support to the Boringssl open source project.
Microsoft added support in Windows 10 RS2 at the beginning of 2017 (later back ported to RS1) .  Edge and IE use that platform support.  It is also available to other applications via system API.  There is also support in ADFS.
NGINX has an open source module
Token Binding support for Apache
Openssl patches in opensource
Ping Identity has tested patches to Java and set up a test environment.
A useful slide share overview
Drafts using token binding exist in the OAuth work group and for OpenID Connect.


John Bradley is the document shepherd and the responsible area director is Eric Rescorla.