"Decentralized Identity and Self-Sovereign Identity (SSi) on the Celo Platform."


In a world increasingly dependent on digital interactions, the need for robust and secure identity solutions has become paramount. Traditional centralized identity systems often fall short in protecting user data and privacy. However, a revolutionary approach known as self-sovereign identity (SSI) offers an alternative paradigm that empowers individuals to take control of their digital identities. In this article, we will delve into the concept of SSI and explore how it can be implemented on the Celo platform, revolutionizing the way we think about identity management.


Before we embark on our exploration of decentralized identity and SSI on the Celo platform, let’s ensure we have a solid understanding of the foundational concepts. Familiarity with blockchain technology, specifically Celo, is crucial to grasp the principles and mechanisms underlying SSI. Additionally, knowledge of cryptographic protocols, public-key infrastructure, and digital signatures will enhance your comprehension of the technical aspects involved in building SSI solutions.


This is a list of what we’ll cover :spiral_notepad:

  • :white_check_mark: Step 1: Project setup
  • :white_check_mark: Step 2: Write smart contract
  • :white_check_mark: Step 3: Deploy smart contract
  • :white_check_mark: Step 4: Integration with frontend

Developers can leverage Celo for innovative, secure, and user-centric identity solutions.

  • Rethinking Identity

    The Case for Self-Sovereign Identity (SSI): We challenge the traditional notion of identity by introducing self-sovereign identity. Explore the concept of SSI as a paradigm shift that puts individuals back in control of their digital identities. Discuss the drawbacks of centralized identity systems and how SSI empowers users to manage their own identities and data.

  • The Celo Advantage

    Embracing Blockchain for SSI: Discover why Celo is the perfect platform for building self-sovereign identity solutions. Uncover the unique features that make Celo stand out, such as its robust blockchain infrastructure, mobile-first design approach, and focus on accessibility. Discuss how Celo’s architecture aligns with the principles of SSI and enhances privacy, security, and user empowerment.

  • Designing User-Centric Identity Experiences

    Simplicity and user experience are paramount in SSI. Explore the key considerations when designing user-centric identity applications on the Celo platform. Discuss techniques for streamlining onboarding, data management, and interaction with verifiable credentials. Highlight the importance of intuitive interfaces and empowering users to control their data.

  • Overcoming Challenges

    Privacy, Security, and Interoperability: Address the challenges developers may face when implementing SSI on Celo. Dive into topics such as privacy-enhancing technologies, cryptographic protocols, secure key management, and decentralized storage solutions. Discuss the importance of interoperability and emerging standards in creating a seamless and interconnected SSI ecosystem.

  • Realizing the Potential

    Exciting Use Cases for SSI on Celo: Illustrate the real-world impact of SSI on the Celo platform through compelling use cases. Explore how SSI can revolutionize industries such as finance, healthcare, supply chain, and governance. Showcase the benefits of verifiable credentials, data ownership, and transparent identity verification processes.

  • The Contrarian Future

    Embracing the Power of SSI: Challenge the status quo and encourage developers to embrace the contrarian perspective of self-sovereign identity on the Celo platform. Highlight the potential for reshaping digital interactions, fostering trust, and empowering individuals. Discuss the role developers play in driving the adoption of SSI and shaping a more inclusive, privacy-preserving future.

Step 1: Project setup

First, we will create a new directory for our project and initialize the project with npm.

mkdir celo-ssi && cd celo-ssi

# Initialize project with npm
npm init -y

Next, we will install Hardhat and dotenv to save the environment variables.

# Install Hardhat
npm install --save-dev hardhat

# Install dotenv
npm install dotenv

Now, we will create a .env file to store the environment variables.

touch .env

Open the .env file and add the following environment variables.

# .env

Next, we will initialize our project with Hardhat.

# Initialize Hardhat
npx hardhat

After successful initialization, we will make changes to the hardhat.config.js file. Please open the file and change it to the following:

require("dotenv").config({ path: ".env" });

/** @type import('hardhat/config').HardhatUserConfig */
module.exports = {
    solidity: {
        version: "0.8.15",
        settings: {
            optimizer: {
                enabled: true,
                runs: 200,
			url: process.env.RPC_URL,
			chainId: 44787,
			accounts: {
				mnemonic: process.env.MNEMONIC,
				path: "m/44'/60'/0'/0",

Step 2: Write smart contract

Now, create a new file called Identity.sol in the contracts directory and add the following code:

spdx-license-identifier: MIT
pragma solidity 0.8.15;

contract Identities {
    // Write your code here

First, we will define a license for our smart contract. Then, we will specify the compiler version. Finally, we will create a contract called Identities.

struct Profile {
    string name;
    uint256 age;
    address wallet;

Next, we will define a struct called Profile that will store the user’s name, age, wallet address, and activation status.

mapping(address => Profile) private profiles;

Then, we will create a mapping called profiles that will map the user’s wallet address to their profile.

function createProfile(string memory _name, uint256 _age) public {
    profiles[msg.sender] = Profile(_name, _age, msg.sender);

Next, we will create a function called createProfile that will allow users to create their profile.

function getProfile(address _wallet) public view returns (Profile memory) {
    return _profiles[_wallet];

Then, we will create a function called getProfile that will allow users to retrieve their profile.

The final code for the Identity.sol file is as follows:

// SPDX-License-Identifier: MIT
pragma solidity 0.8.15;

contract Identities {
    struct Profile {
        string name;
        uint256 age;
        address wallet;

    mapping(address => Profile) private _profiles;

    function createProfile(string memory _name, uint256 _age) public {
        _profiles[msg.sender] = Profile(_name, _age, msg.sender);

    function getProfile(address _wallet) public view returns (Profile memory) {
        return _profiles[_wallet];

Step 3: Deploy smart contract

Now, we will create a new file called deploy.js in the scripts directory and add the following code:

const { ethers } = require("hardhat");

First, we will import the ethers library from Hardhat.

async function main() {
	const Contract = await ethers.getContractFactory("Identities");
	const contract = await Contract.deploy();
	console.log(await contract.getAddress());

main().catch((error) => {
    process.exitCode = 1;

Then, we will create an async function called main that will deploy the smart contract and print the contract address.

npx hardhat run scripts/deploy.js --network alfajores

Finally, we will run the deploy.js script using Hardhat.

Step 4: Integration with frontend

Here’s an example of a simple frontend in HTML and JavaScript that interacts with the smart contracts provided above. This example assumes you’re using the web3.js library to interact with Ethereum.

<!DOCTYPE html>
    <title>Profile Management</title>
    <script src="https://cdn.jsdelivr.net/npm/web3@1.5.2/dist/web3.min.js"></script>
    <h1>Profile Management</h1>
    <form id="createProfileForm">
        <label for="name">Name:</label>
        <input type="text" id="name" required><br>
        <label for="age">Age:</label>
        <input type="number" id="age" required><br>
        <button type="submit">Create Profile</button>

    <div id="profileOutput"></div>

        // Initialize web3 and contract variables
        let web3;
        let profileContract;

        // Initialize web3 and the contract
        async function init() {
            // Modern dapp browsers
            if (window.ethereum) {
                web3 = new Web3(window.ethereum);
                try {
                    // Request account access if needed
                    await window.ethereum.enable();
                } catch (error) {
                    console.error("Access denied to accounts:", error);
            // Legacy dapp browsers
            else if (window.web3) {
                web3 = new Web3(window.web3.currentProvider);
            // Non-dapp browsers
            else {
                console.error("No web3 provider detected!");

            // Load the contract
            const contractAddress = "<your_contract_address>";  // Replace with your contract address
            const contractABI = <your_contract_ABI>;  // Replace with your contract ABI
            profileContract = new web3.eth.Contract(contractABI, contractAddress);

        // Handle form submission
        async function createProfile(event) {
            const name = document.getElementById("name").value;
            const age = document.getElementById("age").value;

            try {
                // Call the createProfile function on the smart contract
                await profileContract.methods.createProfile(name, age).send({ from: web3.eth.defaultAccount });

                // Display success message
                document.getElementById("profileOutput").innerHTML = "Profile created successfully!";
            } catch (error) {
                console.error("Failed to create profile:", error);
                // Display error message
                document.getElementById("profileOutput").innerHTML = "Failed to create profile!";

        // Initialize the app
        window.onload = function() {
            document.getElementById("createProfileForm").addEventListener("submit", createProfile);

Make sure to replace <your_contract_address> with the actual address of your deployed smart contract and <your_contract_ABI> with the ABI (Application Binary Interface) of your smart contract. You can obtain the ABI by compiling your smart contract using tools like Truffle or Hardhat.

When you open this HTML file in a web browser, it will display a form where you can enter the name and age for the profile. Upon submission, it will interact with the createProfile function of your smart contract and display a success or error message accordingly.


In this exciting journey, we have explored the transformative power of self-sovereign identity on the Celo platform. By challenging conventional identity systems and embracing the contrarian approach, developers can pave the way for a more secure, user-centric, and empowering digital landscape. As we reimagine the concept of identity, let us join forces on Celo and shape a future where individuals truly own and control their digital identities. Together, we can redefine identity and unleash its full potential on the Celo platform.

Next Steps

For developers looking to explore decentralized identity and self-sovereign identity (SSI) on the Celo platform, the next steps involve diving deeper into Celo’s documentation, experimenting with code examples, and joining the vibrant community of developers working on identity solutions. By actively engaging with the ecosystem and collaborating with other developers, you can unlock the full potential of decentralized identity on Celo and contribute to the advancement of user-centric digital identities.

Remember, the journey toward decentralized identity is just beginning, and your innovative ideas and contributions can make a significant impact in shaping this transformative field.
you can also read this tutorial

About the Author

Clue is an ardent tech enthusiast who finds immense intrigue in the domains of decentralized finance (DeFi), non-fungible tokens (NFTs), and Web3. With a thirst for knowledge, Clue fearlessly immerses itself. you can connect with me on Twitter

in the world of Solidity, constructing decentralized solutions and unraveling the enigmas of blockchain technology.



i hope to see the completion of this tutorial…

Wow, hopefully the tutorial will be approve very soon

Fantastic news! Your proposal has landed in this week’s top voted list. As you begin your project journey, remember to align with our community and technical guidelines, ensuring a high quality platform for our developers. Congratulations! :mortar_board: :seedling:


I will do a review for you


Okay thanks