Yandex Qrator Labs Internet Initiative Japan & Arrcus, Inc. Arrcus Fastly USA National Institute of Standards and Technology This document describes procedures that make use of Autonomous System Provider Authorization (ASPA) objects in the Resource Public Key Infrastructure (RPKI) to verify the Border Gateway Protocol (BGP) AS_PATH attribute of advertised routes. This type of AS_PATH verification provides detection and mitigation of route leaks and improbable AS paths. It also to some degree provides protection against forged-origin prefix hijacks.