Verifiable STI Presentation and Evidence for RTU (VESPER) Use Cases and Requirements

This document describes use cases and requirements for VESPER (Verifiable STI Presentation and Evidence for RTU), an extension to the Secure Telephone Identity Revisited (STIR) framework. VESPER defines a delegate certificate profile that binds telephone number authority, entity identity, and originating provider authorization into a single verifiable trust artifact, grounded in Right-to-Use (RTU) validation and recorded in a public transparency log. The document identifies the trust gaps that motivate this work and describes requirements for verifiable origination authorization.