Caller-ID Vouching and Vetting (CIDVV)

Caller-ID spoofing remains a significant problem in telephony, particularly across inter-domain and international call paths where identity frameworks may not be consistently applied. This document defines Caller-ID Vouching and Vetting (CIDVV), a lightweight verification mechanism that uses short-lived signaling exchanges encoded within the Calling Party Number to confirm that a calling party can receive calls at the Asserted Caller-ID. CIDVV is designed to operate across heterogeneous SIP and SS7/TDM networks without requiring new protocol extensions or persistent identity infrastructure. It relies on existing call routing behavior and intentionally leverages failure responses as a signaling mechanism, using failed call attempts as evidence of number control rather than successful call completion. The mechanism improves resistance to Caller-ID spoofing by requiring demonstrable control of the Asserted Caller-ID, while remaining incrementally deployable and tolerant of intermediate network modification.