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Monitor the Auditor

Cloudflare’s Key Transparency Auditor validates Log audit proofs and provides a signature for them. The Log can then distribute these signatures to its end-users, and provides users with confidence that keys have not been tampered with.

In order to verify our work, you can use Plexi, a CLI tool that allows anyone to perform proof verification locally via a public API.

Features

  • Verify authenticity of a signature, to confirm it has been signed by a given public key
  • Verify the validity of facebook/akd proofs
  • List Logs an Auditor monitors

Installation

EnvironmentCLI Command
Cargo (Rust 1.81+)cargo install plexi

Usage

Use the --help option for more details about the commands and their options.

Terminal window
plexi [OPTIONS] <COMMAND>

Configure your auditor remote

plexi does not come with a default remote auditor, and you will need to choose your own.

You can do so either by passing --remote-url=<REMOTE> or setting the PLEXI_REMOTE_URL environment variable.

A common remote is provided below:

NameRemote
Cloudflarehttps://plexi.key-transparency.cloudflare.com

If you have deployed your own auditor, you can add a remote by filing a GitHub issue.

List monitored Logs

An auditor monitors multiple Logs at once. To discover which Logs an auditor is monitoring, run the following:

Terminal window
plexi ls --remote-url 'https://plexi.key-transparency.cloudflare.com'
whatsapp.key-transparency.v1

Audit a signature

The Key Transparency Auditor vouches for Log validity by ensuring epoch uniqueness and verifying the associated proof.

plexi audit provides information about a given epoch and its validity. It can perform a local audit to confirm the auditor behaviour.

For instance, to verify WhatsApp Log auditted by Cloudflare Auditor, run the following:

Terminal window
> plexi audit --remote-url 'https://plexi.key-transparency.cloudflare.com' --namespace 'whatsapp.key-transparency.v1' --long
Namespace
Name : whatsapp.key-transparency.v1
Ciphersuite : ed25519(protobuf)
Signature (2024-09-23T16:53:45Z)
Epoch height : 489193
Epoch digest : cbe5097ae832a3ae51ad866104ffd4aa1f7479e873fd18df9cb96a02fc91ebfe
Signature : fe94973e19da826487b637c019d3ce52f0c08093ada00b4fe6563e2f8117b4345121342bc33aae249be47979dfe704478e2c18aed86e674df9f934b718949c08
Signature verification: success
Proof verification : success