This question already has an answer here:
I've read that ICANN is the authority dedicated to assigning IP addresses to individual entities, so that no two separate entities are using the same IP address on the internet. It is my understanding that when assigning an IP address, an autonomous system number is also given to the entity. These autonomous system numbers are used by routers in some way to advertise that they have a route to an IP address.
My question is, how does a router know that a route and autonomous system number that they receive from a BGP peer is authentic? Is there a certificate chain of some kind used to prove that the route does indeed go to the entity that ICANN did assign the IP address to? Since an IP address can be multi homed with two or more routes to it, just because there are two routes known by a router doesn't mean that one of them is not real.
Does ICANN regularly publish a list of autonomous system numbers that routers cache?
Can routers choose to ignore ICANN's assignment of IP addresses, in the event that ICANN goes rogue? What's stopping an alt_ICANN from being created and the internet choosing to trust it instead?