Plugin signature verification (signing) is a security measure to make sure plugins haven't been tampered with. Upon loading, Grafana checks to see if a plugin is signed or unsigned when inspecting and verifying its digital signature.
For Grafana to be able to verify the digital signature of a plugin, the plugin must include a signed manifest file, _MANIFEST.txt_. The signed manifest file contains two sections:
- **Signed message -** The signed message contains plugin metadata and plugin files with their respective checksums (SHA256).
- **Digital signature -** The digital signature is created by encrypting the signed message using a private key. Grafana has a public key built-in that can be used to verify that the digital signature have been encrypted using expected private key.
When Grafana starts, it discovers plugins to load. For each discovered plugin it verifies the authenticity of it, and then decides whether to load it or not based on the state of the plugin signature:
If a [backend plugin]({{< relref "../developers/plugins/backend/_index.md" >}}) is not signed, then Grafana will not load or start it. If you try to load a backend plugin with an invalid signature, then Grafana writes an error message to the server log:
While you can allow unsigned plugins using a configuration setting, we strongly advise you not to. For more information on how to allow unsigned backend plugin, refer to [Configuration]({{< relref "../administration/configuration.md#allow-loading-unsigned-plugins" >}}). Allowing unsigned plugins will not skip verifying the authenticity of a plugin if plugin has a _MANIFEST.txt_ file.
If you're developing plugins and run Grafana from source, the development mode is enabled by default and also allow you to run unsigned backend plugins.
