First of all, a node added to tailnet doesn’t not have the ability to decrypt the traffic in tailnet. All it can do to contact other nodes, decrypt traffic users sent to that hidden node, or modify settings in admin console. Furthermore, with tail lock, the coordination server should not be able to add nodes from outside.
Even if an attacker such as the government runs the coordination and relay servers, and the IdP, they will not be able to decrypt any traffic in tailnet.
The secret keys remain on device, and traffic is end to end encrypted. There is no mechanism in
the client agents to send out the secret keys. The coordination server receives the public keys and metadata.
I see I did have a misunderstanding. I believe there is still the meta data angle, but yes, private keys on endpoints would ensure E2EE. I will update my comment.
Can you clarify?