Zero Knowledge Technology: The Ultimate Privacy Tool?

Zero-knowledge technology, specifically the zero-knowledge proof, is one of the most interesting yet complex developments that could revolutionize the cryptography and blockchain space. Let’s take a look at what exactly zero-knowledge proofs are and get a beginner’s understanding of how they work.

The idea of zero-knowledge proofs was first theorized in 1985 by a group of researchers that included Silvio Micali, the future founder of the Algorand blockchain. The general idea of a zero-knowledge proof is that it is a method in which someone can prove they know something without directly revealing the information. This may sound complicated because it is an idea that many have never been exposed to before. It is like being able to prove you know something without having to tell anyone what you know, a concept so abstract and counter-intuitive that it seems impossible. 

There are two main roles in a zero-knowledge proof: the prover and the verifier. The prover’s role is to prove that they know secret information. The verifier’s role is to determine whether or not the prover is being honest. The verifier does this by testing the prover multiple times, giving them questions or tasks that could only be done by someone who knows the information. 

A common example used to help understand zero-knowledge proofs is called the color blind test. Say there are two people, a prover and a verifier. The prover has two balls and needs to prove to the verifier that they are different colors, but the verifier is color blind. To prove this, the prover gives the balls to the verifier and has the verifier secretly switch what hands they hold each ball in, and ask the prover to tell if the balls are switched or not. If the prover does this correctly once, there is a 50% chance that he is being truthful and a 50% chance he guessed correctly, so the experiment is repeated several times until the probability that he is lying is significantly low. This was a low-effort way for the prover to tell the verifier that the balls are different colors without the verifier ever having seen the colors of the balls. 

Another example has to do with a 2D graph and two points on the graph. Let’s say that the prover wants to prove to the verifier that they know about two secret points on the graph. They could prove this by giving the verifier a line that has the two points in question on the line. There are infinitely many lines that could be made in the graph, so this provides enough evidence to the verifier that they know where the two points are. 

As demonstrated in the first example, there is no 100% guarantee that what is being said is true, so there is a level of chance that the prover could be lying. However, with proper tests and precautions, the chance of this can become so significantly low that it is nearly impossible. 

There are several uses for zero-knowledge proofs that will revolutionize the way we share data and how blockchains work. With digital identities and zero-knowledge proofs, one could prove their age or citizenship without having to give up the sensitive and valuable data of their identification document. It could also be used for digital voting, and ensure that anonymous voting is valid and counted. Another use case is in blockchains, as it allows for fully private transactions that are fully auditable and trustless. In fact, this technology has already been implemented in privacy-oriented cryptocurrencies like ZCash and Monero and has yet to be broken.

Zero-knowledge technology is still incredibly new and has a long way to go before it becomes a staple of cryptography. However, massive strides are being made in its research, and it will one day be possible to create zero-knowledge proofs for all sorts of things, including Ethereum smart contracts and financial applications. This will revolutionize the way we interact with our data and cause a resurgence in individual privacy.

By Lincoln Murr

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