Abstract: A method of operating a server system is provided. The method includes providing an updated authentication tree data structure based on a pruning authentication tree data structure, wherein the pruning authentication tree data structure includes a first set of N data blocks and a first root hash value, the data blocks of the first set being associated to the first root hash value via an associating authentication path. The updated authentication tree data structure includes a second set of data blocks determined based on pruning M data blocks from the first set, the updated authentication tree data structure including a pruning hash value determined based on the pruned data blocks, and including a second root hash value determined based on the second set, each of the data blocks of the second set being associated to the second root hash value via an associating authentication path.

Abstract: Provided is a workflow system for managing a workflow including a plurality of places; a token, the token representing a deliverable; a transition between places, the transition consuming a predetermined token from a first place and creating a predetermined token in a second place.