Remove auth_enc config option

As we didn't hear any voices requesting this feature, we removed the
option to disable it and always have peer connection auth encrypted.

closes #1518
follow-up #1325

docs/specification/configuration.rst

@@ -122,9 +122,6 @@ like the file below, however, double check by inspecting the
     # Does not work if the peer-exchange reactor is disabled.
     seed_mode = false
 
-    # Authenticated encryption
-    auth_enc = true
-
     # Comma separated list of peer IDs to keep private (will not be gossiped to other peers)
     private_peer_ids = ""
 

docs/specification/secure-p2p.rst

@@ -65,9 +65,7 @@ are connected to at least one validator.
 Config
 ------
 
-Authenticated encryption is enabled by default. If you wish to use another
-authentication scheme or your peers are connected via VPN, you can turn it off
-by setting ``auth_enc`` to ``false`` in the config file.
+Authenticated encryption is enabled by default.
 
 Additional Reading
 ------------------