Introduction to Zero-Knowledge Proof (ZKP)

Almost every individual with a smartphone uses apps that collect and, most probably, resell their personal data. On the other hand, people who don’t use apps also have their phone operating system or their network provider collecting their data. So, how can people get complete control over their data?

In recent times, blockchain and cryptography have definitely garnered a lot of attention for safeguarding user data. Zero-Knowledge Proof is one of the cryptographic mechanisms that establish the foundation of cryptographic protocols. Let us explore more information about the Zero-Knowledge Protocol, its features, benefits, and applications.

Basically, the Zero Knowledge Proof involves a person providing proof to another person about having some sort of information without revealing the information. The person providing the proof is known as the prover, and the other person is known as the verifier. Therefore, the zero-knowledge protocol helps in communicating the proof of possessing specific information without actually revealing the information.

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The applications of zero-knowledge proof in blockchain transactions primarily refer to the identification functionalities. Just by providing the final output, the prover can show to the verifier that they can complete a process or compute something without actually revealing the computational process or the input. On the other hand, the verifier is capable of learning only about the output.

Distinguishing Zero-Knowledge Proofs

  1. Completeness: The zero-knowledge proof should convince the verifier about the fact that the prover actually knows what they claim to know.
  2. Soundness: In event of false information, the protocol cannot convince the verifier that the information provided by prover is true.
  3. Zero-knowledge: Even if the statement is true or false, the verifier cannot know anything other than that.

Proof of Identity

Types of Zero-Knowledge Proofs

The interactive ZKPs generally involve performing a series of actions for convincing the verifier about a specific fact. The only setback with interactive variant of ZKPs is limited transferability and requirement for proving facts to the verifier multiple times.

The non-interactive ZKPs, on the other hand, involve delivery of proof that anyone could verify on their own. In this case, the verifier has to set a random challenge that the prover has to solve. Furthermore, an interactive ZKP could convert to a non-interactive variant by using a hash function for selecting the challenge. It would not involve any form of interaction with the verifier. Non-interactive ZKPs don’t require repeated transactions between the verifier and prover. The proof in non-interactive ZKPs is present in a single message, provided to verifier from the prover.


Applications of Zero-Knowledge Proofs

Authentication Systems

Private Purchases

Private Blockchains

Secure Bitcoin Transactions


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