Tailscale [0] says the private keys never leave the device.
“Security
Tailscale and WireGuard offer identical point-to-point traffic encryption.
Using Tailscale introduces a dependency on Tailscale’s security. Using WireGuard directly does not. It is important to note that a device’s private key never leaves the device and thus Tailscale cannot decrypt network traffic. Our client code is open source, so you can confirm that yourself.”
That is true as far as it goes, but how does your node learn the public keys of the other nodes in your tailnet? My understanding is that they are provided by the coordination server, so you have to trust that the public key the coordination server gives you is actually the one for your peer device.
Tailnet lock helps mitigate this by requiring that node public keys are signed by a trusted signing node, but it isn't bulletproof.
Like what? I'm saying both sides of the connection would be given the wrong public keys by the coordination server. The private keys of which would be held by a MITM.
To add to that, they also provides Tailnet lock [0], which protects from the only way the coordination server can mess with the tailnets, by connecting unauthorized nodes.
