Part 6/9:
While such permissioned blockchains might be able to change records quickly and discreetly, they sacrifice the key security guarantees that come with open, proof-of-work-based blockchains. Andreas paints a vivid picture: If governments or entities with control over permissions decide to alter records, they could do so instantaneously. The only thing preventing them from doing so secretly is the system's design—if it lacks the robust security proofs of proof-of-work, it’s potentially vulnerable.