US Patent 11061887 Event verification receipt system and methods

An event is registered in at least one node server in a directed data structure, which comprises a computationally linked series of nodes such that each node encodes information included in at least one preceding node. Within at least selected nodes of the directed data structure after at least one initial node, a representation of at least one history data structure is included and has a highest-level value computed based on inputs of lowest level input values, at least one said lowest level input value encoding node-specific information of at least one preceding node. In a verification phase, a purportedly valid lowest level input value is verified by recomputing the corresponding highest-level value from the representation of the history data structure included in the corresponding node.