RPKI is a system that provides validation of IP address and AS number ownership through the use of digital certificates. It aims to reduce routing leaks and hijacking by allowing routers to verify that the origin AS of a route matches what is published in the RPKI database. The key components of RPKI are trust anchors maintained by Regional Internet Registries, Route Origin Authorizations (ROA) that are published by network operators, and validators that check BGP routes against the ROA database.