Post-Quantum Readiness and Hybrid Signing Architecture in Mobile Non-Custodial Wallets: The VKX Wallet Security Model

This document describes the security architecture implemented in the VKX Wallet, including a Post-Quantum Readiness Layer, hybrid signing model, device integrity gating, secure storage strategy, and proof registry system. The architecture introduces an incremental approach to cryptographic hardening in mobile non-custodial wallets, combining classical ECDSA signatures with off-chain post-quantum integrity proofs using ML-DSA (Dilithium). This publication serves as a defensive publication to establish prior art and publicly document the VKX Wallet security model.