Which of the following steps is not required from a central party (e.g. Scrooge) to maintain an immutable/trustworthy blockchain?

		Publish the hash of the latest block
		Publish the signature of the hash of the latest block
		Publish its public key
		Publish its secret key

Which of the following statement precisely explains why in bitcoin mining it is a Nash equilibrium for all miners to follow the longest chain rule (assuming that all miners have negligible computing powers compared to the global computing power)

		When all other miners follow the longest chain rule, it is better to follow the longest chain rule too
		When all other miners do not follow the longest chain rule, it is better to not follow the longest chain rule either
		When all other miners follow the longest chain rule, it is better to not follow the longest chain rule
		When all other miners do not follow the longest chain rule, it is better to follow the longest chain rule

In Bitcoin mining, which of the following can a malicious node do, even though it may not be in its best interest?

		Create valid transactions originating from someone elses address
		Prevent a valid transaction from getting any confirmations forever
		Ignore the longest valid branch rule when proposing a new block
		Delete a transaction in the last block of the longest chain