Summary
- Zero-knowledge proofs (ZKPs) pre-date the invention of the Bitcoin protocol (1985 v 2009)
- It is an important piece of cryptography that underlies the next iteration of blockchain technology.
- They are not inherently a technology exclusive to blockchains, they are integrated in.
- In a blockchain context, the use cases of ZKPs can be leveraged to enhance privacy, scaling, and others.
- Read more Crypto Council explainers.
What is a Zero Knowledge Proof (ZKP)?
Here is how the inventors of ZKPs define it: “A zero-knowledge protocol is a method by which one party (the prover) can prove to another party (the verifier) that something is true, without revealing any information apart from the fact that this specific statement is true.”
In general, a zero-knowledge protocol must satisfy the following criteria:
- Completeness: If the input is valid, the zero-knowledge protocol always returns ‘true’. Hence, if the underlying statement is true, and the prover and verifier act honestly, the proof can be accepted.
- Soundness: If the input is invalid, it is theoretically impossible to fool the zero-knowledge protocol to return ‘true’. Hence, a lying prover cannot trick an honest verifier into believing an invalid statement is valid (except with a tiny margin of probability).
- Zero-knowledge: The verifier learns nothing about a statement beyond its validity or falsity. This requirement also prevents the verifier from deriving the original input (the statement’s contents) from the proof.
How is it used?
Technology that allows for the transmission of data / information between parties without relieving sensitive information can be transformative in digital identity, digital payments, digital infrastructure scaling, authentication and many more.
Within the blockchain development landscape, the potential of ZKPs garner the most amount of attention given the greenfield of opportunities.
For example, some of the ZKP use cases that are being developed right now are: on-chain and off-chain scaling solutions (zkRollups), private (but verifiable) transactions integrated into the Ethereum Virtual Machine (zkEVM), and others that guarantees both privacy and scalability while maintaining a trustless environment for information and value to exchange.
Being able to integrate privacy preserving technology into inherently public blockchain networks means that developer and entrepreneurs can achieve even more use cases for crypto, especially in the world of digital identity and authentication.
Further Reading:
How to explain zero-knowledge proofs to your children
Zero Knowledge Proofs: An illustrated primer – A Few Thoughts on Cryptographic Engineering
