Zero Knowledge Proofs : What exactly are they?
Digital Identities, digital transactions, secure identity are all the rage right now. Guard your personal credentials, dont share more than required information, so many warnings! It feels like netizens are constantly in a state of war with hackers on the prowl, who want to misuse personal information. And state of war means a constant vigilance. But that can be exhausting.
What is the solution then? How to share information without sharing information? Quite the paradox isnt it. This is where Zero Knowledge Proofs come into play. ZK Proof is a Privacy-enhancing Technology(PET).
What is Zero-Knowledge Proof ?
ZK, or zero-knowledge, is a cryptographic technique that allows one party to prove to another party that they know a specific piece of information, without revealing any additional information about that piece of information. This means one can prove their identity or possession of a piece of knowledge (for e.g. a valid KYC document) by giving only essential information and not revealing any sensitive information.
The core of this concept is to prove one has possession of knowledge without actually revealing it. Thus, it means that user says that they know Z without actually saying what Z is. What remains to be verified is the truth of the statement.
Zero Knowledge Proof Properties
A zero-knowledge proof (ZKP) has the following properties
- Completeness: If the information provided by the prover is true, then a ZKP method must enable the verifier to verify that the prover is telling the truth.
- Soundness: If the information provided by the prover is false, then a ZKP method must allow the verifier to refute that the prover is telling the truth.
- Zero-knowledge: The verifier knows nothing more than whether the prover telling the truth or not.
Types of Zero Knowledge Proofs
There are two types of Zero knowledge Proofs –
- Interactive zero knowledge proof : The prover and verifier communicate wherein the verifier challenges the prover. The prover then replies the challenges till the verifier is satisfied.
- Non-interactive zero knowledge proof : Proof that is given to the verifier can be independently verified by the verifier. This requires higher computational power as compared to Interactive ZK Proof as the proof usually is something that is to be solved or decoded.
Use Cases for ZK Proofs
- Blockchains use ZK Proofs for ZK Rollups
- Self Sovereign Identity Solutions use ZK Proofs for identity proof and verification
Are ZK Proofs the ultimate solution for information privacy ?
Although ZK Proofs are an amazing solution for preserving data privacy, there a few challenges —
No Guarantees : Since ZK Proofs are a probabilistic methodology, there is no guarantee that the prover is telling the truth. There is always a small margin for falsehood.
Computationally Complex : Due to complex algorithms in non-interactive ZK Proofs, the computationaly power required is large. In interactive ZK Proofs the number of interactions can be large.
Despite these drawbacks ZK Proofs are currently one of the best methods in use. Constant research is helping bring out more efficient ways of ZK Proofs.
