Vehicular blocktrees

Every day autonomous vehicles will independently generate terabytes of unverified data. In the case of an accident involving multiple stakeholders with various (dis)incentives to honestly report, the question arises how to reconstruct the accident scene with validated and authenticated data without relying on a centralized authority. In this paper, we introduce Proof of Physics (PoP), a consensus mechanism whereby environmental (sensor) data is persisted only after audit and computational agreement that the recorded event occurred. Vehicles perform permissionless (e.g., requiring no centralized authority) writes of the signatures of their recorded events and associated content. The blocktree aggregates the verified data enabling querying over validated historic events. We evaluate the blocktree security by analyzing the ability of a malicious attacker to successfully fork the vehicle blocktree. We show that the attacker's success probability approaches negligible as the number of vehicle witnesses and confirmations increases.