ATIS 1000089.v002

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 six different mechanisms: Delegated Certificates, LEveraging Models for Originating eNtity authentication - Full Attestation with Entity Identity in a Secure Token (LEMON-TWIST), Enterprise Certificates, Extended Validation (EV) Certificates with TN Letter of Authorization (TNLoA), Central TN Database, and Distributed Ledger Technology (DLT), 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."