To help reduce well-known threats against BGP including prefix misannouncing and monkey-in-the-middle attacks@ one of the security requirements is the ability to validate the origination Autonomous System (AS) of BGP routes. More specifically@ one needs to validate that the AS number claiming to originate an address prefix (as derived from the AS_PATH attribute of the BGP route) is in fact authorized by the prefix holder to do so. This document describes a simple validation mechanism to partially satisfy this requirement.