Blockchain synchronisation protocol

A computer program embodied on non-transitory computer-readable storage media and configured so as, when run on one or more processors, to perform a method of determining whether blockchain nodes have a synchronised view of a blockchain, wherein the method is performed by a first blockchain node and comprises:

• sending i) a first block height corresponding to a most recent block of the blockchain stored by the first blockchain node and ii) a first timestamp corresponding to a current time held by the first blockchain node, to a second blockchain node, wherein the first block height and the first timestamp are comprised in a single first message;
• receiving i) a second block height corresponding to a most recent block of the blockchain stored by the second blockchain node, and ii) a second timestamp corresponding to a current time held by the second blockchain node, from the second blockchain node, wherein the second block height and the second timestamp are comprised in a single second message;
• and
• determining whether the first and second blockchain nodes have a synchronised view of the blockchain based on the first and second block heights and the first and second timestamps.