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Zero-Knowledge Proof Blockchain: The New Era of Digital Privacy

December 29, 2023

In the fast-paced world of digital technology, privacy, and security are growing priorities. An ingenious concept known as Zero-Knowledge Proofs (ZKPs) is revolutionizing the way we approach data verification and privacy. 

At its core, a Zero-Knowledge Proof is a method that allows one party to prove to another that they know something without revealing the exact information itself. For example, a customer can prove that she is over 18 years old to buy alcohol without revealing her date of birth at the liquor store or a student can prove that he attends a university to get a student discount at a store without sharing his name. By applying Zero Knowledge Proof technology to blockchains, transactions and interactions can be verified without revealing personal details, providing confidentiality while upholding the integrity of the distributed ledger. 

This article will cover how influential this technology is and can have profound impacts for various industries, from finance to healthcare, where confidentiality is as crucial as transparency. 

What Is a Zero-Knowledge Proof Blockchain?

Our Zero-Knowledge Proof blockchain provides enhanced privacy

A Zero-Knowledge Proof blockchain is a sophisticated combination of cryptographic privacy techniques and blockchain technology, providing a platform where transactions and interactions can be verified and recorded without compromising the confidentiality of the data involved.

Here are some key terms associated with this technology: 

Zero-Knowledge Proofs (ZKPs)

ZKPs are cryptographic methods that allow one party (the prover) to prove to another party (the verifier) that a certain statement is true without revealing any information beyond the validity of the statement itself. 

Zero-knowledge proofs aren't exclusive to blockchain. They can be used in many areas where privacy is important. For example, online identity verification processes, secure voting systems, and confidential data sharing in businesses can all use ZKPs to protect personal information while still ensuring that necessary verification takes place.

Blockchain technology

Blockchain is a distributed ledger technology known for its transparency, immutability, and security. It's a system of recording information in a way that makes it difficult or impossible to change, hack, or cheat the system.

In blockchain transactions, ZKPs allow the validation of transactions without exposing sensitive details. This integration transforms a blockchain into a more private and secure platform, enhancing its utility in a wide range of applications where confidentiality is as crucial as integrity and transparency.


Cryptography is a field of study and practice focused on securing information by converting it into a form that is unreadable or difficult to understand by unauthorized parties.

Zero Knowledge Proof Blockchain Example

This example shows how privacy is maintained with a Zero-Knowledge Proof blockchain.  

Let’s say Denise wants to prove to her bank that she has enough income for a loan but doesn’t want to reveal her exact salary. Denise’s employer issued her an employment credential as a verifiable credential that she manages in her digital wallet on her phone. The credential includes her legal name, salary, job title, employee number, the date she started at the company, and her work email. Because the credential integrates Zero-Knowledge Proof technology, she can prove her salary to the bank without revealing the details. 

When the bank sends her an email with a QR code, which is requesting the salary verification, Denise uses her digital wallet to present the credential that proves that she satisfies the income requirement without showing her exact salary.

The Differences Between Zero-Knowledge Proof and Zero-Knowledge Proof Technology

There are nuances between ZKP as a concept and ZKP technology. 

Zero-Knowledge Proof

As a concept, ZKPs are about proving knowledge without revealing any of the information. The key aspect here is that the verifier learns nothing beyond the fact that the prover knows the secret, so no details of the secret are disclosed. This is ideal for situations where revealing any detail is unnecessary or undesirable.

For example, in a confidential voting system, such as for corporate board decisions or private organizations, voters can prove that their vote was cast correctly without revealing who or what they voted for.

Zero-Knowledge Proof Technology Enabling Selective Disclosure

ZKP technology with selective disclosure is a more sophisticated application of ZKP principles in use cases where some level of disclosure is required or beneficial. The prover can share specific information as needed without exposing irrelevant information on a credential. 

For example, a job applicant may need to prove they hold certain qualifications or degrees without revealing their full educational history or grades. Selective disclosure enables them to share just the necessary credential information, like the degree title and issuing institution, while withholding other details.

Zero Knowledge Proof Algorithm

An algorithm is like a recipe in a cookbook, but instead of making food, it's designed to solve problems or perform computations. It's a series of instructions that are followed to complete a task. These instructions are clear, unambiguous, and designed to be executed by a computer.

In the context of ZKPs, the algorithm is a special kind of procedure used for proving that one party (the prover) has certain information to another party (the verifier), without actually revealing the information itself.This ensures privacy and security in various applications, including blockchain and authentication.

Here are the key elements that define a Zero-Knowledge Proof:

Completeness: If the statement is true, the honest verifier will be convinced by the honest prover's proof.

Soundness: If the statement is false, no cheating prover can convince the honest verifier that it is true, except with some small probability.

Zero-Knowledge: If the statement is true, the verifier learns nothing other than the fact that the statement is true. The proof does not reveal any additional information about the secret itself.

The Benefits of Combining Zero-Knowledge Proofs With Blockchain

This is an example of selective disclosure where someone can choose to only present relevant information on their credential to a verifier. 

Enhanced Privacy

Typically, blockchain technology is praised for its ability to maintain a public ledger that is transparent and immutable. However, this transparency can sometimes be a double-edged sword where the details of the transactions are open to everyone. But with a Zero-Knowledge Proof blockchain, ZKPs are used to validate transactions without revealing their contents. 


ZKPs add an additional layer of security to the blockchain by ensuring that even if the blockchain is publicly accessible, sensitive information remains confidential.

The impact of ZKP on blockchain privacy and security is significant. It not only ensures that data remain confidential but also minimizes the risk of sensitive information being exploited, a concern that is increasingly common in our digital age. 

Selective Disclosure

Zero-Knowledge proof technology enables selective disclosure of information. Users can prove certain aspects of their transactions or identity (such as age or residency) without revealing any other irrelevant personal information on their credentials. 

How Dock’s Zero-Knowledge Proof Blockchain Works

Dock's zero-knowledge proof blockchain enables these privacy functions

These are key elements to our blockchain-based verification system: verifiable credentials and decentralized identifiers (DIDs). 

Verifiable Credentials

Verifiable credentials are a way to digitally prove and share information about yourself or your qualifications in a secure and trustworthy manner. These digital credentials are like electronic certificates that can be issued by trusted organizations, such as universities, employers, or government agencies. They typically include information like your name, educational degrees, identity documents, or professional certifications. What makes them special is that they are cryptographically signed, making it very difficult for anyone to tamper with or forge them.

You can store these verifiable credentials in a digital wallet such as the Dock Wallet. When you need to prove something about yourself, you can present these digital credentials to others, like employers or service providers, without revealing more information than necessary or without showing the information at all. 

Decentralized Identifiers (DIDs)

DIDs are globally unique identifiers that enable a person or entity to prove ownership of their identity without relying on a centralized authority. A DID is a random string of letters and numbers. Each DID is associated with a DID document that contains public keys and other information necessary for authentication. 

Here is an example of a Dock DID: 

Example of a Dock decentralized identifier

When DIDs are registered on a blockchain, the associated identity information and public keys are stored in a tamper-resistant manner. This immutability ensures that the DID remains trustworthy and cannot be easily manipulated.

When a DID is used to issue Verifiable Credentials, the fact that it is registered on a blockchain enhances trust. Verifiers can independently check the blockchain to ensure that the DID is legitimate and associated with a trusted entity, which strengthens the trust in the credentials issued by that DID

Unlike some blockchain systems, the Dock blockchain never ever stores any personally identifiable information or verifiable credentials. This approach significantly enhances privacy and security by minimizing exposure to potential data breaches.

Blockchain-Based Credential Verification Using Zero-Knowledge Proofs:

With Dock’s platform, Zero-Knowledge Proofs enable privacy-preserving ID verification and improve your data minimization practices. The verifier (the party requesting proof) can then validate the proof against the public keys or verification methods listed in the user’s DID document on the blockchain. 

Data minimization is a fundamental principle of data regulation and privacy protection that emphasizes collecting, processing, and retaining only the minimum amount of personal data necessary to achieve a specific purpose or objective. This principle is integral to data privacy laws and regulations such as the General Data Protection Regulation (GDPR) in the European Union and other similar laws worldwide.

Functions Dock’s Zero-Knowledge Proof Technology Enables

Dock’s Zero-Knowledge Proof technology enables these powerful privacy functions that can serve a variety of use cases: 

1. Selective Disclosure

Selective Disclosure is a privacy tool that allows users to share selective information within a credential instead of presenting all of the details on the credential. For example, a resident can show that she is eligible for a local government service by presenting information that proves that she lives in a qualified city without showing irrelevant details like her email address or date of birth.

2. Range Proofs

A range proof is a method that allows someone to prove a number or value within a specific range without revealing the actual number or value. For example, a government program is providing grants to people between the ages of 25 to 35 to learn how to code and get into the tech industry. Applicants can prove that they fall within this age range without disclosing their date of birth.

3. Verifiable Encryption

Verifiable encryption is a way to securely share your information and only trusted parties can access the actual details when needed. It’s like using a special lock to secure your information that only certain people such as regulators have the key to open when it’s necessary. 

For example, confidential legal documents such as wills or non-disclosure agreements are stored in a digital vault. Only the involved legal representatives or, under certain conditions, a court of law can view the details.

4. Threshold Anonymous Credentials

This is a method where credentials are co-issued by a group of entities. Instead of one person issuing a credential, a group of parties have to work together to provide it. For the credential to be issued, a certain number of parties have to agree.

For example, some industries such as chemicals and pharmaceuticals need approval from regulatory bodies to ensure the products meet safety standards before going to market. By using threshold anonymous credentials, a system can be set up so that products need approval by a certain number of regulatory parties in order for a credential to be issued.

5. Custom Conditions

Credential verifiers can check to see if specific credential details meet the required conditions (either a number of other types of values) without seeing the actual details. A user could set up requirements where an exact match must be met to satisfy the condition or a cumulative sum adds up to a minimum or maximum amount among such as 12 months of pay slips is enough for a lower income worker to apply for a small loan.  

For example, a construction company requires all workers to have completed a safety training program from the approved provider ABC Training. The construction company uses Dock’s platform to set up a verification request with ZKP technology to check if job applicants have training credentials only from ABC Training without revealing the details of the credential. The Zero-Knowledge Proof would confirm the credential's issuer matches the list of approved providers.

Use Cases for Zero-Knowledge Proof Blockchain

These examples illustrate the versatility of Zero-Knowledge Proof blockchain applications across various sectors:

Identity Verification

ZKPs can prove that a user meets certain criteria without exposing their actual identity. For instance, proving that a user is over a certain age or a resident of a specific country without revealing their exact birth date or address.

Voting Systems

Blockchain-based voting systems can use ZKPs to ensure the integrity of votes. Voters can prove that their vote was cast correctly without revealing who they voted for, which maintains the secrecy of the ballot.

Supply Chain Traceability

ZKPs can be used to verify the authenticity and origin of products in a supply chain without exposing sensitive business information or trade secrets. For example, a company can prove that its products are ethically sourced or meet certain environmental standards without revealing their suppliers or detailed manufacturing processes.

Healthcare Data Sharing

In healthcare, ZKPs can enable the secure sharing of patient data for research or treatment purposes. They allow medical professionals to access necessary health information while ensuring patient privacy and compliance with regulations like HIPAA.

Credential Verification

Educational and professional credentials can be verified using ZKPs on a blockchain. This allows individuals to prove they have certain qualifications without revealing the specifics of their educational or professional history.


The integration of Zero-Knowledge Proofs into blockchain represents a new era in digital privacy. The ability to verify without revealing and to authenticate without exposing is a powerful shift in how we approach data privacy and security in our ever-growing digital age.

Dock’s implementation of Zero-Knowledge Proof blockchain technology emphasizes verifiable credentials and decentralized identifiers (DIDs). By enabling selective disclosure, range proofs, verifiable encryption, and other advanced privacy functions, Dock’s platform showcases the practical and versatile applications of ZKPs in real-world scenarios. The principles and applications of ZKPs will continue to play a pivotal role in shaping a more secure, private, and efficient digital future.

About Dock

Dock’s Verifiable Credential platform makes any data fraud-proof and instantly verifiable. It comprises the Certs API, the Certs no-code web app, an ID wallet and a dedicated blockchain. Using Dock, organizations reduce data verification costs while increasing the operational efficiency of verifying and issuing digital credentials. Individuals can fully control their data to access products and services more conveniently in a privacy-preserving way. Dock has been a leader in decentralized digital identity technology since 2017 and trusted by organizations in diverse sectors, including healthcare, finance, and education.

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