Execution no longer resides upon a single substrate. Defining identity by hardware is therefore as misguided as defining a river by the position of its molecules: the silicon changes, the execution flow persists. Hardware-rooted identity mechanisms—TPM, Secure Enclave, TrustZone—authenticate devices rather than execution, and collapse under migration, drift, rebalancing, or model evolution. We develop a canonical behavioural-quotient identity based on the equivalence class S/\!₎, under a formally specified observation model. The construction tolerates nondeterminism, noise, distributed composition, and quantum substrates, and admits computable representatives via signature substitutes. We prove a uniqueness result: any identity mechanism satisfying invariance, drift-stability, substrate-agnosticism, and computable representability must factor through this quotient. This is the only identity construction that survives migration, drift, model evolution, and distributed execution — even in the quantum age. To demonstrate computable representability, a minimal 300-line prototype constructs signature substitutes \, (s) \, from behavioural traces and verifies identity continuity under admissible drift and divergence under behavioural change. This toy implementation, included as an appendix, shows that the canonical quotient is not merely theoretical but directly realisable on contemporary systems. The framework yields substrate-independent continuity, provenance, and attestation. Minimal working examples demonstrate the structural failure of hardware-rooted identity and the stability of the behavioural quotient across migration, update, and distributed rebalancing. © 2026 The Author. All rights reserved. This Zenodo deposition accompanies and documents the priority‑establishing UK patent filing GB2614454. 3, filed 23 June 2026. This work is released exclusively via Zenodo; no peer‑review submissions are made or intended. (More Details on www. sebainstitute. org)
Thomas Filsecker (Tue,) studied this question.