---
title: Monitor the Auditor
description: Verify Key Transparency audit proofs locally using the Plexi CLI tool.
image: https://developers.cloudflare.com/core-services-preview.png
---

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### Tags

[ CLI ](https://developers.cloudflare.com/search/?tags=CLI) 

# 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 ↗](https://github.com/cloudflare/plexi), a CLI tool that allows anyone to perform proof verification locally via a public [API](https://developers.cloudflare.com/key-transparency/api/).

## Features

* Verify authenticity of a signature, to confirm it has been signed by a given public key
* Verify the validity of [facebook/akd ↗](https://github.com/facebook/akd) proofs
* List Logs an Auditor monitors

## Installation

| Environment                                                     | CLI Command         |
| --------------------------------------------------------------- | ------------------- |
| [Cargo ↗](https://www.rust-lang.org/tools/install) (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:

| Name       | Remote                                        |
| ---------- | --------------------------------------------- |
| Cloudflare | https://plexi.key-transparency.cloudflare.com |

If you have deployed your own auditor, you can add a remote by filing a [GitHub issue ↗](https://github.com/cloudflare/plexi/issues).

### 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


```

```json
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```