Robust Decentralised Proof-of-Position Algorithms for Smart City Applications

Motivated by the ever growing use of location-based services, we present a decentralised class of algorithms called Tree-Proof-of-Position (T-PoP). Most of the current proofs of location are centralised, thus forgoing verifiablity and privacy for the users. Decentralised solutions also exist, but they suffer from drawbacks that make them unsuitable for realistic, adversarial use cases. T-PoP algorithms rely on the web of interconnected devices in a smart city to establish how likely it is that an agent is in their claimed position. T-PoP operates under adversarial assumptions, where some agents are incentivised to be dishonest. We present a theoretical model for T-PoP and its security properties, and we validate this model through a large number of Monte-Carlo simulations. We specifically focus on two instances of T-PoP and analyse their security and reliability properties under a range of adversarial conditions. Use-cases and applications are discussed towards the end of the paper.