crypto
	encryption
	bit-commitment
	proof of work
encryption
necessity of randomness in encryption
one-time pad
	partial information leakage
	indistinguishable random variables
	defn of security
		for all two distinct messages
	construction
	one-timeness of construction
	problem: requires large key size
statistical indistinguish
computational indistinguishability
	non-uniform attackers
defn of message indistinguishability
defn of OWF
	=> P\ne NP