User-generated messages encapsulating selections from each of a plurality of entities for a selection task having a selection option are received via one or more interfaces presented by a selection processing system. For each selection, a different share of a signing key is obtained that has an identity associated with the selection task. For each selection, a different partial signature is generated by signing the messages using the associated share of the signing key. The partial signatures are combined into a threshold signature if a number of entities for a selection option specified by the task exceeds a pre-defined threshold. Data characterizing the results of the selection task can then be provided.