I just read though and did a quick search of
https://github.com/lightning/bolts/blob/master/07-routing-gossip.mdand did not see anything mentioning encryption.
Odd, but you have to have some certificate someplace that you send your side to when they connect.
Didn't check, IS it even encrypted? I mean it's 'sudo public' information being sent.
-Dave
I guess it is, for privacy and security reasons.
As far as I understand from here, it uses the node ID (a pubkey) to encrypt the traffic.