Identity Protocol Documentation Circom 2.0 Blog

Prove your access rights, not your identity

iden3 is a next-generation private access control based on self-sovereign identity, designed for decentralised and trust-minimised environments.

Privacy for all

Everyone has the right to liberty and equality, the right freely to participate in their community, and the right to privacy.

The aim of the iden3 protocol is to empower people and create a more inclusive and egalitarian foundation for better human relationships through open-source cryptography and decentralised technologies.

Privacy by design


Open source

Future-proof tech stack for self-sovereign identity

Censorship-resistant infrastructure

The iden3 protocol is based on Ethereum and thus inherits its properties such as a high degree of decentralisation and a security profile.

To provide the best possible user experience and make self-sovereign identity available to all, the protocol will include an ID sponsor module.

This component will allow developers to design their applications in such a way that a developer-run account covers all the costs of interacting with the blockchain for users.

Additionally, the protocol will soon be scalable at Layer 2 thanks to zkRollup technology. Enabling high capacity at ultra-low cost on a public and permissionless infrastructure to guarantee access for all.

Battle-tested cryptography

The use of the Zero-Knowledge proving system zk-SNARK defines not only a security standard (as this cryptography is the leading paradigm for blockchain scalability) but is also the most powerful way to protect privacy.

Zero-Knowledge Proofs based on zk-SNARK allows that any computational condition can be represented by an arithmetic circuit.

This important property offers universality and flexibility for zkProof that can be generated to prove anything about identity (with quick verification time).

iden3 comes with a Rapid-PLONK scheme that offers a single trusted setup that can be shared with multiple applications, streamlining development.

Practical standards

iden3 has developed a novel proof-query language that allows simple configuration of the type of identity claims required for private verification.

A claim is the most basic statement which can be issued for identity and JSON-LD schemas are used to describe data of the identity claims.

iden3 will support DID, JSON-LD and JSON schema to be interoperable with W3C standards for Verifiable Credentials.

The Circom 2.0 compiler (written in Rust with dedicated dev tooling) is used to create Zero-Knowledge Proofs for the circuits.

Versatility of applications

The main idea of the iden3 protocol is that each identity is self-soverign and can issue claims on another identity (which can be for an individual, an organisation or a system/machine).

This simple and unique characteristics can lead to creation complex adaptive systems and the following use cases:

  • Decentralised trust models / web-of-trust

  • Decentralised ID verification / proof-of-personhood

  • Decentralised voting systems

  • Interaction with DeFi / dApps / Web3

  • Decentralised payment identifiers

  • Private access control

  • Authentication and authorisation

  • Signing documents and private messaging

  • Supply chain and IoT

  • NFT ownership

iden3 features for simple interaction with Web3

  • Self-soverign identity generation and management

  • zkProofs generation and verification

  • Proof-query language

  • Authentication and authorisation

  • Multi-identifier ID model (with cross-auth methods)

  • ID profile based on verifiable claims and documents

  • Mobile ID wallet app reference + mobile SDK

  • P2P communication between identities

  • Claim lifecycle management (issuance, revocation)

  • Expressive claims syntax

  • Decentralised naming service

  • Key rotation and ID recovery

  • ID sponsor model (cost-free solution for users)

  • Interoperability with DID and Verifiable Credentials standards from W3C

Powerful language to build zero-knowledge circuits: Circom 2.0

Circom is the developer tool of choice for building zero-knowledge applications. It was created by iden3 and its effectiveness and reliability have been proven in implementations such as Polygon Hermez, Dark Forest, Zkopru and Tornado Cash.

More about Circom 2.0  →

Intuitive identity control

iden3 identity wallet app (for iOS and Android) is an open reference for end-users to receive trusted claims and generate zkProofs for private access. It also allows direct communication with another identity.

Identity wallet