Protecting sensitive data in a distributed ledger system using a blockchain channel hierarchy

A blockchain hierarchy comprises an arrangement of blockchain channels organized such that a blockchain channel at a lower level feeds data to another blockchain channel, e.g., a relatively higher level. At least one blockchain channel comprises a private autonomous subset of peers in the set of peers that comprise the blockchain network. Within that particular subset, one of the peers is elected as a leader entity, which has the capability of also joining another private or public blockchain channel, e.g., one at a higher level in the hierarchy. The leader entity includes a capability to enforce a data protection policy within the blockchain channel that it leads. To this end, the leader filters or declassifies data based on some task-specific (or blockchain channel-specific) data protection policy, and it then makes that data available to one or more other blockchain channels in the hierarchy (directly or indirectly).