ATIS 1000089

This Technical Report describes use cases where a Signature-based Handling of Asserted information using toKENs (SHAKEN) Originating Service Provider (OSP) may not have complete locally available information to establish a verified association between a calling telephone number (calling TN) and its direct Customer, as the basis for assigning a "full attestation" value to particular calls. In addition, this report summarizes a few different mechanisms: Delegated Certificates, Extended Validation (EV) Certificates with TN Letter of Authorization (TNLoA), and Central TN Database, that have been proposed to provide the OSP with additional information regarding the entity placing a call and the telephone numbers that entity has a valid association with in order to support the OSP marking the call with the highest attestation level.