Token Binding

Document Charter Token Binding WG (tokbind)
Title Token Binding
Last updated 2019-03-27
State Approved
WG State Active
IESG Responsible AD Roman Danyliw
Charter Edit AD Roman Danyliw
Send notices to (None)


Web services generate various security tokens (e.g. HTTP cookies, OAuth
tokens, etc.) for web applications to access protected resources. Currently
these are bearer tokens, i.e. any party in possession of such token gains
access to the protected resource. Attackers export bearer tokens from client
machines or from compromised network connections, present these bearer tokens
to Web services, and impersonate authenticated users. Token Binding enables
defense against such attacks by  cryptographically binding security tokens to a
secret held by the client.

The tasks of this working group are as follows:

1. Specify the Token Binding protocol v1.0.
2. Specify the use of the Token Binding protocol in combination with HTTPS.

It is a goal of this working group to enable defense against attacks that
involve unauthorized replay of security tokens. Other issues associated with
the use of security tokens are out of scope. Another goal of this working group
is to design the Token Binding protocol such that it would be also useable with
application protocols other than HTTPS. Specifying alternative application
protocols is not a primary goal.

The main design objectives for the Token Binding protocol, in no particular

1. Allow applications and services to prevent unauthorized replay of security
tokens. 2. Allow strong key protection, e.g. using hardware-bound keys. 3.
Support both first-party (server generates a token for later use with this
server) and federation (server generates a token for use with another server)
scenarios. 4. Preserve user privacy. 5. Make the Token Binding protocol useable
in combination with a variety of application protocols. 6. Allow the
negotiation of the Token Binding protocol without additional round-trips. 7.
Allow the use of multiple cryptographic algorithms, so that a variety of secure
   hardware modules with different cryptographic capabilities could be used
with Token Binding. 8. Propose Token Binding specification that can be
implemented in Web browsers (but is not limited to them). E.g. Web browsers
require that the same bound security token must be presentable over multiple
TLS sessions and connections.

The working group will use the following documents as a starting point for its

- draft-popov-token-binding-00;
- draft-balfanz-https-token-binding-00.

This WG will collaborate with other IETF WGs, in particular with the TLS,
HTTPbis and Oauth WGs and with the W3C webappsec WG.