Editing Cryptographic hash function (section)

== Illustration ==
An illustration of the potential use of a cryptographic hash is as follows: [[Alice and Bob|Alice]] poses a tough math problem to [[Alice and Bob|Bob]] and claims that she has solved it. Bob would like to try it himself, but would yet like to be sure that Alice is not bluffing. Therefore, Alice writes down her solution, computes its hash, and tells Bob the hash value (whilst keeping the solution secret). Then, when Bob comes up with the solution himself a few days later, Alice can prove that she had the solution earlier by revealing it and having Bob hash it and check that it matches the hash value given to him before. (This is an example of a simple [[commitment scheme]]; in actual practice, Alice and Bob will often be computer programs, and the secret would be something less easily spoofed than a claimed puzzle solution.)