Options: (A)hacker breaks security for altruistic or at least non-malicious reasons. (B) hacker of ambiguous ethics and/or borderline legality, often frankly admitted. (C) someone outside computer security consulting firms that are used to bug test a system prior to its launch, looking for exploits so they can be closed. (D) None of these 2
Options: the lock is obtained only after the transaction has processed., the lock is obtained before the transaction has processed., the lock never needs to be obtained., transactions that are best suited are those with a lot of activity.