Collectively Witnessing Log Servers in CT

Document Type Expired Internet-Draft (individual)
Last updated 2016-04-21 (latest revision 2015-10-19)
Stream (None)
Intended RFC status (None)
Expired & archived
plain text pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document proposes a backward-compatible extension to CT enabling log servers to obtain compact collective signatures from any number of well-known "witness" servers, which clients can check without gossip to verify that log server records have been widely witnessed. Collective signatures proactively protect clients from man-in-the- middle attackers who may have stolen the private keys of one or more log servers, even if the attacker controls the client's network access, the client is unwilling to gossip for privacy reasons, or the client does not wish to incur the network bandwidth and/or latency costs of gossip.


Bryan Ford (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)