A computer-implemented method for determining which of one or more nodes of a distributed ledger network satisfy one or more operating performance benchmarks required to operate as trusted third party nodes, the distributed ledger network comprising a plurality of nodes (102a-102n, 104a-104m), the plurality of nodes comprising a group of nodes , wherein each node in the group of nodes includes functionality for acting as a trusted third party node on a distributed ledger transaction, the method comprising: performing a plurality of operating performance tests on one or more selected nodes (104a-104m) of the group of nodes , wherein each operating performance test comprises sending a plurality of test messages to each selected node (104a-104m) over a predetermined time period, wherein each selected node receives a plurality of operating performance tests at random or pseudo-random time instances over a predetermined time interval; receiving operating performance data associated with each selected node (104a- 104m) in relation to the operating performance tests; aggregating operating performance statistics for each selected node (104a-104m) based on the received operating performance data, wherein aggregating the operating performance statistics for each selected node comprises calculating the operating performance statistics for each selected node based on the frequency at which the received operating performance data associated with the selected node satisfy corresponding target performance thresholds in relation to the one or more operating performance benchmarks; and indicating to the distributed ledger network those selected nodes (104a-104m) satisfying the one or more operating performance benchmarks for acting as a trusted third party for distributed ledger transactions over the distributed ledger network based on the aggregated operating performance statistics. performing a plurality of operating performance tests on one or more selected nodes (104a-104m) of the group of nodes , wherein each operating performance test comprises sending a plurality of test messages to each selected node (104a-104m) over a predetermined time period, wherein each selected node receives a plurality of operating performance tests at random or pseudo-random time instances over a predetermined time interval; receiving operating performance data associated with each selected node (104a- 104m) in relation to the operating performance tests; aggregating operating performance statistics for each selected node (104a-104m) based on the received operating performance data, wherein aggregating the operating performance statistics for each selected node comprises calculating the operating performance statistics for each selected node based on the frequency at which the received operating performance data associated with the selected node satisfy corresponding target performance thresholds in relation to the one or more operating performance benchmarks; and indicating to the distributed ledger network those selected nodes (104a-104m) satisfying the one or more operating performance benchmarks for acting as a trusted third party for distributed ledger transactions over the distributed ledger network based on the aggregated operating performance statistics. <EOS>