Zero Knowledge Proof Explained By Examples скачать в хорошем качестве

Zero Knowledge Proof Explained By Examples

Zero-Knowledge Proof, abbreviated as ZKP, is a novel way to prove a fact without leaking any privacy information. The emergence of Zero-Knowledge Proof is for one of the most important things about us, the protection of privacy data. Nowadays, ZKP is widely used in many block-chain projects which can effectively provide a way to authenticate the user without leaking user's privacy in a public environment. Nowadays, there are more and more use cases which can use ZKP to authenticate users in our daily life. For example, if we want to prove that a student already passed the exam but don't want to show the actual mark for the exam. Also, when we are purchasing some insurance policies, we just want to show the insurance company that we don't have cancer, but we don't want to show more details about our health, and so on.  Generally, the proof is not the same as the strict mathematical proof which uses axioms and logic. Most of the ZKP proof are based on mathematical Probability which means the result can proved from statistical point of view. The verifier will randomly ask the prover for the proof. If the prover can always provide the correct result, after a few times, although the possibility of failure of the proof is not zero, but very close to it. So, technically that small chance of failure can be ignored and the proof is considered as successful. Let's consider some examples about Zero-Knowledge Proof. Alice want to prove to Bob that she has the key to a room. How can she do it? Of course she can give Bob the key to open the door, and thus prove that she has the key. But this will enable Bob to see the key. If Alice has other privacy information such as age or home addresses on the key, they will be released to Bob as well. What we can do to enable Alice to prove the fact without showing the key to Bob? A possible solution can be: Alice will tell Bob that she can grab something from the room which Bob knows, and show it to Bob, and thus indirectly prove that she has the key. Let's take a look at another question. Alice have two balls which has red and green color. Her friend Bob has color blindness and cannot identify colors. How Alice prove to Bob that the two balls have different colors? One solution might be. Bob put two balls in his hands. In each round he can randomly choose to swap or not swap the balls in his hand without letting Alice see the swap action. Then he will ask Alice to identify if he has swapped the balls. Since Alice doesn't have color blindness, she can correctly the color of balls in Bob's hands. After a few rounds, If Alice can always reply correctly, Bob will know the two balls will have different colors because the possibility of failure is very low. The third example of ZKP is the well-known Ali Baba cave. Location A and Location B is in a cave and are separated by a door which can be opened via keys. If Alice want to prove to Bob that she has the key to the door, what she can do to completed the proof without showing the key to Bob? The possible solution would be: Alice can randomly choose to stand at location A or location B, and Bob don't know her location. Bob will randomly pick up a side, either A or B, and ask Alice to walk out through that cave. For example, if Alice is standing at location A and Bob asked her to walk out via the B side, she need to use the key to open the door. After a few rounds, Bob will believe that Alice has the key to the door, and Alice do not need to show the key to Bob. Attribution: Image from Pixabay: https://pixabay.com/zh/photos/keyboar...