One of the biggest advantages of blockchain technology is the degree of information transparency it offers. All transactions can be traced, and the details are visible to anyone on the network, not just the parties involved.
But depending on the domain of application and the mechanics implemented, blockchain can also maintain a high level of privacy. Zero-knowledge proof (ZKP) is one of the ways to verify data input while maintaining anonymity.
What Zero-Knowledge Proof is and How it Works
Zero-knowledge proof is a mathematical model that is applied to verify information without sharing or exposing it. It is a probabilistic assessment: two parties validate the data using indirect signs and a set of queries. That's why the result may not provide the level of complete certainty that revealing the information would but it proves that the data is overwhelmingly probable.
Here's an easy example. Imagine a box with 10 black pens, 7 red pens, and 3 blue ones. If a person took one pen from the box, let's say it is a red pen and needs to prove to another person that it's not a black pen without revealing what color it is, they can convince the other person that there are still 10 black pens in the box. In terms of blockchain, the verification process is more complex and can be either interactive or non-interactive.
An interactive zero-knowledge proof verification process consists of three phases that can be repeated multiple times:
Witness: A prover sends a witness or proof that the information is correct to the verifier. Challenge: The verifier sends a challenge to the prover to see if they truly know the information. Response: The prover calculates the response.
A non-interactive ZKP doesn't involve an interactive process between the two parties but requires additional software.
For the system to work as described, it must have three fundamental traits:
Completeness, which means both the prover and the verifier do not lie and strictly follow the rules. Then the verifier will be easily convinced and the process wouldn't seek external help or additional steps.
Soundness, which implies the ability to prove that one party is lying. If a prover tries to fool the verifier, the latter won’t be convinced under any circumstances. Zero-knowledge, the non-disclosure of information.
Advantages Zero-Knowledge Proofs Offer
A ZKP oddly simplifies the process of information exchange and verification. Since no party receives the underlying data, there is no need for complicated encryption methods. That, in turn, shortens the transactions on blockchains and solves the issue of information storage.
A zero-knowledge proof method also improves security. The less information a company knows, the lower the likelihood is that it will be stolen if the platform is exploited.
Disadvantages of Zero-Knowledge Proofs
The biggest shortcoming of the ZKP method is the amount of computing capacity it requires to validate the information. The verification process is lengthy and can't be easily scaled.
The algorithm is in an early stage of adoption. There's no common standard for interacting with the apps and platforms that have adopted the ZKP model, which further limits its number of use cases.
Closing Thoughts
Data privacy and security are important subjects, and the zero-knowledge proof method has much to offer the discussion. To see a greater number of use cases and general adoption of this verification process, we first need to resolve the problem of scalability. The blockchain industry is already struggling with network congestion. Prolonging the verification process on the blockchain would only aggravate the problem.