Summary

Blockchain consensus works when each node conducts frequent checks with all other nodes to see if its image of the blockchain matches others’. This makes the blockchain invulnerable to hacks because a successful hacker would need to gain access to at least 51 percent of the nodes and simultaneously make the same change to all of them in order to convince the blockchain network the hacked version of the truth is correct. This is technologically infeasible due to the intrinsic security within each blockchain node.