Starting with Unity 6.6, the Unity Editor supports signing of asset packages and checks for digital package signatures whenever you import an exported asset package.
Package signatures are part of Unity Core Standards.
A package signature is a cryptographic identifier that helps verify where a package came from and ensures it wasn’t changed after the developer created it. Package signatures make it easier for everyone to confirm a package’s origin and integrity, and spot any unauthorized changes or tampering. The recommended best practice is to sign all packages you create. Taking this simple step helps members of the Unity community feel more confident when using your packages.
Sign the asset packages you export and associate them with one of your organizations, so others who import your asset package can determine who created and owns it.
To sign your asset package, make sure you’re signed in to the Unity Editor and connected to the internet.
Note: Both signed and unsigned asset packages are fully backwards compatible with older versions of the Unity Editor. Older Editors don’t verify the signature.
For more information about package signatures, refer to Introduction to package signatures.