A zero-knowledge proof (ZKP), also known as a zero-knowledge protocol, is a mathematical method for determining the accuracy of information without exposing it. This article will explain what ZKP is, how it works, the numerous forms of Zero-Knowledge Proof, and its advantages as well as disadvantages.
What Is Zero-Knowledge Proof
Zero-Knowledge Proof is a cryptographic technique in which no information is given during a transaction other than the exchange of a value known to both the prover and the verifiers (the two ends of the process).
The concept behind the zero-knowledge proof is that a person may demonstrate to another user that they are aware of an absolute value without exposing any other or additional information.
How Does Zero-Knowledge Proof Work?
A zero-knowledge proof allows you to demonstrate the truth of a proposition without exposing its contents or how you got the truth. Zero-knowledge protocols rely on algorithms that accept some data as input and produce ‘true’ or ‘false’ as output.
A zero-knowledge protocol must meet the following requirements:
Completeness: If the input is genuine, the zero-knowledge protocol always returns ‘true’. As a result, the evidence can be accepted if the underlying proposition is true and the prover and verifier act honestly.
Soundness: It is theoretically impossible to deceive the zero-knowledge protocol into returning ‘true’ if the input is faulty. As a result, a deceptive prover cannot dupe an honest verifier into believing an incorrect assertion is true (except with a tiny margin of probability).
Zero-Knowledge: The verifier learns nothing about a statement other than its truth or falsehood (they have “zero knowledge” of it). This criterion also precludes the verifier from deducing the original input (the contents of the statement) from the proof.
In basic form, a zero-knowledge proof is made up of three elements: witness, challenge, and response.
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Witness: The prover of a zero-knowledge proof wishes to demonstrate knowledge of some secret information. The hidden information is the “witness” to the proof, and the prover’s supposed knowledge of the witness produces a series of questions that can only be answered by a person with knowledge of the information. As a result, the prover begins the proving process by selecting a question at random, computing the answer, and passing it to the verifier.
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Challenge: The verifier selects another question from the collection at random and asks the prover to answer it.
- Response: Accepting the query, the prover computes the answer and returns it to the verifier. The answer of the prover helps the verifier to determine if the former truly has access to the witness. The verifier selects extra questions to ask to ensure the prover isn’t guessing blindly and receiving the correct answers by chance. By repeating this exchange numerous times, the chance of the prover falsifying the witness’s knowledge decreases considerably until the verifier is satisfied.
The structure of an ‘interactive zero-knowledge proof’ is described above. Early zero-knowledge protocols employed interactive proving, which needed back-and-forth communication between provers and verifiers to check the truth of a statement.
Types of Zero-Knowledge Proofs
There are two types of ZeroKP algorithms:
Interactive ZKP
The actions linked with the ideas are concerned with mathematical probability. In interactive ZKP, a prover must persuade a specific verifier and then repeat the procedure for each verifier. In interactive ZKPs, the prover must perform a set of acts to persuade the verifier of a certain fact.
Non-Interactive ZKP
Non-interactive ZKPs lack voluntary engagement between the verifier and the prover. In non-interactive ZKP, a prover provides proof that anybody may check, and the verification process can also be deferred to a later stage. They require particular software for a better mechanism of non-interactive ZKPs.
Zero-Knowledge Proof Use Cases
Below are the common use cases of the Zero-Knowledge Proof;
Messengers on Blockchain
Although today’s messengers have claimed to be encrypted, unencrypted blockchain might be the next great thing in technology. With the assurance of an unencrypted yet strong solution, ZKPs and blockchain may collaborate to develop a value-added messaging platform that is secure for everybody.
File System Controls
ZKPs can aid in the addition of additional levels of protection to files and logins. As a result, ZKPs can make it difficult for hackers or manipulators to modify and recover data.
Storage Protection
ZKPs incorporate a security protocol with the data in the storage unit. The access channels are protected by powerful protections, resulting in a highly secure and smooth environment.
Privacy
The most significant worry with private blockchain transactions is the various flaws in traditional methods. The effective combination of ZKP with private blockchain transactions can result in a robust hacker-proof procedure.
Data Security
Banks and hospitals, for example, must protect their critical data from unauthorized access. Together, ZKPs and blockchain can make data access impossible.
Zero-Knowledge Proof Pros and Cons
Pros;
Simplicity
The most noticeable feature of ZKPs is their simplicity. It does not require any software skills to use, yet it may provide superior solutions that have an influence on our everyday life. Furthermore, because it is entirely unencrypted while remaining extremely secure, it may provide the best of both worlds simultaneously.
Security
When it comes to transferring information, ZKPs are incredibly secure. As a result, a user may utilize it with confidence without needing to study the codes or analytics to grasp its fundamentals.
Saves time
ZKPs reduce the time necessary for blockchain transactions, providing consumers with value in a noble way.
Privacy
The most valued feature of ZKPs is the protection of its users’ privacy. It never involves sensitive data transfer and is thus inherently private.
Safety
Users of ZKPs are aware of the need for ZKPs to share data, and they can stay away from any company that needs access to personal information without a valid reason.
Cons;
Hardware costs
Creating zero-knowledge proofs requires extremely sophisticated computations that are best executed on specialist equipment. Because these pieces of equipment are pricey, they are frequently out of reach for the average person. Furthermore, applications that intend to leverage zero-knowledge technology must consider hardware expenditures, which may raise end-user prices.
Proof verification costs
Verifying proofs also necessitates complicated calculations, which raises the expense of incorporating zero-knowledge technologies into applications. This cost is especially important when it comes to demonstrating computation. ZK-rollups, for example, spend 500,000 gas to validate a single ZK-SNARK proof on Ethereum, whereas ZK-STARKs need even higher fees.
Trust Assumptions
The Common Reference String (public parameters) is created once in ZK-SNARK and is accessible for re-use by parties wishing to participate in the zero-knowledge protocol. Public parameters are generated through a trusted setup ceremony in which participants are presumed to be truthful.
However, there is no method for consumers to check the honesty of participants, thus users must accept the developers’ word for it. Because the randomness employed to generate the string is publicly verifiable, ZK-STARKs are devoid of trust assumptions. Meanwhile, researchers are working on non-trusted ZK-SNARK setups to improve the security of proving procedures.
Quantum Computing Threats
For encryption, ZK-SNARK employs elliptic curve cryptography. While the ECDSA technique is now secure, the advent of quantum computers may compromise its security model in the future.
Because it employs collision-resistant hashes for encryption, ZK-STARK is thought to be immune to the danger of quantum computing. Collision-resistant hashing is more difficult for quantum computing methods to break than public-private key pairs used in elliptic curve encryption.
