Cross-Platform Policy Parental Control (X-PPC) for Household Governance

This document defines the Cross-Platform Policy Parental Control (X-PPC) protocol for consistent policy enforcement across heterogeneous household endpoints including Desktop PCs, Mobile Devices, Gaming Consoles, Handhelds, and Smart TVs. X-PPC 1.0.0 specifies a 3-tier hybrid trust-chain architecture designed to enable policy enforcement during periods of network unavailability. The protocol defines interoperable message formats, signature requirements, and enforcement semantics that OS and device vendors can implement using platform-appropriate mechanisms.