Witness

Overview

This repository contains libraries and binaries for running witnesses. A witness verifies that logs are evolving in an append-only manner and counter-signs checkpoints that represent an append-only evolution from any previously witnessed checkpoints. These witnessed checkpoints can be consumed by clients that want protection against split-views.

Users wishing to run this should start with the OmniWitness.

API

The witness is an HTTP service that stores checkpoints it has seen from different verifiable logs in a sqlite database. This is a very lightweight way to help detect or even prevent split-view attacks.

The witness provides three API endpoints (as defined in api/http.go):

• /witness/v0/logs returns a list of all logs for which the witness is currently storing a checkpoint.
• /witness/v0/logs/<logid>/update acts to update the checkpoint stored for logid.
• /witness/v0/logs/<logid>/checkpoint returns the latest checkpoint for logid, signed by the witness.

Running the witness

Most users wanting to run a witness will simply deploy the OmniWitness, which is preconfigured to witness all known logs using the checkpoint format.

Support

• Mailing list: https://groups.google.com/forum/#!forum/trillian-transparency

• Slack: https://transparency-dev.slack.com/ (invitation)