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Strange question, is it thesis time? One zero knowlede proof example that almost everyone is familiar with is the two coloured balls example. Let’s see if I can remember it: You have two balls, one green and one red, identical in every way except colour. You have a colour-blind friend who sees them as identical, and he doesn’t believe you when you say that they are different. You want to prove that they are in fact different, but do not want to reveal which is green and which is red. So you give your mate the balls, one in each hand, and tell him to put the balls behind his back and mix them up (or not) while you can’t see them. You can then tell him with 100% accuracy whether he switched the balls (or not) each time simply by looking at the colour. If there was not a difference in colour, the best you could do over time would be guess with 50% accuracy. You can prove that the balls are different colours, but with this method, your mate didn’t gain any knowledge (zero knowledge, in other words) as to which ball is red and which is green.