VRRP - support for authentication

Virtual Router Redundancy Protocol (VRRP) is a vendor neutral FHRP protocol that does not inherently support authentication. According to RFC 5798, earlier versions did support authentication, however, they were removed because "operational experience showed that they did not provide any real security and would only cause multiple masters to be created."

However, Cisco has implemented its own proprietary feature called VRRP Authentication that provides a way to add authentication to VRRP.

Links:

https://forum.networklessons.com/t/vrrp-virtual-router-redundancy-protocol/1151/72?u=lagapides

https://networklessons.com/cisco/ccie-routing-switching/vrrp-virtual-router-redundancy-protocol

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipapp_fhrp/configuration/15-mt/fhp-15-mt-book/fhp-vrrp.html#GUID-B1CB24C0-2526-4790-A701-0105FDA69FC8

https://www.rfc-editor.org/rfc/rfc5798#page-33