An apparatus in an illustrative embodiment comprises a processing platform that includes one or more processing devices each comprising a processor coupled to a memory. The processing platform is configured to communicate over at least one network with one or more additional sets of processing devices associated with at least a first blockchain-based cryptocurrency system. Each of at least a subset of the one or more processing devices of the processing platform comprises a trusted execution environment, such as a secure enclave. The processing platform is further configured to release from the trusted execution environment of a given one of the one or more processing devices of the processing platform a first blockchain transaction on the first blockchain-based cryptocurrency system, and to condition release of a second blockchain transaction relating to the first blockchain transaction on receipt of at least a specified threshold amount of evidence of confirmation of the first blockchain transaction on the first blockchain-based cryptocurrency system.