... previouslyindentified validator known as the destination AS. The originating AS computes a MAC using a shared key over a concatenation of an initial authenticator value(e.g., 0), the path, and the fields that do ... (e.g., are nested). Hence, the validator can validate not only the path,but can validate that a) path was traversed the ASes in the order indicated bythe path, and b) no intermediate ASes were added ... ownership as a tree emanating from ICANN, asillustrated in Figure 3.ASes are assigned an AS number (ASN) in a similar manner, with ICANN beingthe ultimate authority for delegating numbers. ASNs are...