Zero Knowledge and Identity

ZK is anticipated as one of the technologies that will undoubtedly change Web3. When it comes to ensuring the privacy, security and integrity of blockchain applications ZK looks quite promising.

Trust is backbone of Blockchain and ZK would be helpful in securing user identity and data, so that they can authenticate themselves in a trustless world.

In today’s world privacy is the main point of concern. An individual won’t want to reveal his complete identity to get a small job done, but at the same time the verifier also needs the information to confirm if the things are fine to proceed. The answer to this scenario is Zero Knowledge.

Understanding Zero Knowledge with an example

The classic Ali Baba cave example gives deeper insights about the ZK concept. But for beginners it might be confusing and unclear to get started with understanding the concept of ZK. So let’s discuss another interesting example.

When you visit to a club, at the entry you are asked to show a proof that you are 18+ in age. Normally you share your ID card which contains your photo, date of birth and other private details like your residential address or your work place details. It’s not desired that just to verify an individual’s age all other private details would also be revealed. Now what’s the solution to this ?

The answer is ZK proofs. In the above scenario, the individual can generate a ZK proof that he/she is 18+ in age which can be stored as a claim. Now any organisation or individual who wants to verify the claim can do so easily without having a need to look at ID card and check the date of birth. It’s a win-win situation for both the parties as the prover don’t need to reveal his ID card and the verifier can verify is the prover is 18+ in age or not.

Now, for the online world a user has his/her identity too. Many platform demands for the gmail authentication and unnecessary access to mails and other details. Same is the case with web3 platforms, once the user connects his wallet to the platform, indirectly his entire on-chain data is revealed to that platform via his blockchain wallet address.

Existing ZK and Identity Solutions and Tools

Polygon ID

Polygon ID is the first ever to be powered by zero-knowledge (ZK) cryptography, a privacy and blockchain scaling technology. It provides Blockchain-based ID for decentralized and self-sovereign models backed by zero-knowledge native protocols for ultimate user privacy.


You can leverage ZK proofs using trinsic platform to build your end-to-end identity solution. Trinsic’s API makes it easy to build identity products that helps users manage their data and identity.


iden3 is a next-generation private access control based on self-sovereign identity, designed for decentralised and trust-minimised environments. The main idea of the iden3 protocol is that each identity is self-soverign and can issue claims on another identity. The iden3 protocol is based on Circom circuits which is the backbone of the protocol.


Semaphore consists of a smart contract and zero-knowledge proof components which work in tandem. The on-chain proof verification and identity state is maintained and handled by smart contract. The zero-knowledge components work off-chain to create identities, manage groups and generate proofs.


The above discussion would have established a curiosity and a fundamental understanding of zero knowledge proofs and related tools and platforms built over it.

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