SPATE: Small-Group PKI-Less Authenticated Trust Establishment
Establishing trust between a group of individuals remains a difficult problem. Prior works assume trusted infrastructure, require an individual to trust unknown entities, or provide relatively low probabilistic guarantees of authenticity (95% for realistic settings). This work presents SPATE, a primitive that allows users to establish trust via device mobility and physical interaction. Once the SPATE protocol runs to completion, its participants' mobile devices have authentic data that their applications can use to interact securely (i.e., the probability of a successful attack is 2?24). For this work, one leverages SPATE as part of a larger system to facilitate efficient, secure, and user-friendly collaboration via email and file-sharing services.