Example: Identity Verification Library

This example library, EvireIdentityVerificationLibrary, is designed to facilitate identity verification and management for dApps operating in the real-world asset (RWA) domain on the Evire blockchain. 

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/**
 * @dev This library provides functions to facilitate identity verification and management for dApps
 *      operating in the real-world asset domain (RWA) using the Evire blockchain.
 */
library EvireIdentityVerificationLibrary {
    
    // Event emitted when a new KYC provider is added
    event KYCProviderAdded(address indexed provider);

    // Event emitted when a user completes the KYC verification process
    event UserVerified(address indexed user, uint256 timestamp);

    struct KYCProvider {
        bool isApproved;
        string name;
        string jurisdiction;
    }

    struct UserKYC {
        bool isVerified;
        uint256 timestamp;
        address verifiedBy;
    }

    mapping(address => KYCProvider) private kycProviders;
    mapping(address => UserKYC) private userKYCRecords;

    /**
     * @dev Adds a new KYC provider to the approved list.
     * @param provider Address of the KYC provider
     * @param name Name of the KYC provider
     * @param jurisdiction Jurisdiction of the KYC provider
     */
    function addKYCProvider(address provider, string memory name, string memory jurisdiction) external {
        require(provider != address(0), "Invalid provider address");
        require(!kycProviders[provider].isApproved, "Provider already approved");

        kycProviders[provider] = KYCProvider({
            isApproved: true,
            name: name,
            jurisdiction: jurisdiction
        });

        emit KYCProviderAdded(provider);
    }

    /**
     * @dev Verifies a user's identity through an approved KYC provider.
     * @param user Address of the user to verify
     */
    function verifyUser(address user) external {
        require(user != address(0), "Invalid user address");
        require(kycProviders[msg.sender].isApproved, "Caller is not an approved KYC provider");

        userKYCRecords[user] = UserKYC({
            isVerified: true,
            timestamp: block.timestamp,
            verifiedBy: msg.sender
        });

        emit UserVerified(user, block.timestamp);
    }

    /**
     * @dev Checks if a user is verified.
     * @param user Address of the user to check
     * @return isVerified Boolean indicating if the user is verified
     * @return timestamp Timestamp when the user was verified
     * @return verifiedBy Address of the KYC provider who verified the user
     */
    function isUserVerified(address user) external view returns (bool isVerified, uint256 timestamp, address verifiedBy) {
        UserKYC storage userRecord = userKYCRecords[user];
        return (userRecord.isVerified, userRecord.timestamp, userRecord.verifiedBy);
    }

    /**
     * @dev Retrieves the details of an approved KYC provider.
     * @param provider Address of the KYC provider
     * @return name Name of the KYC provider
     * @return jurisdiction Jurisdiction of the KYC provider
     */
    function getKYCProviderDetails(address provider) external view returns (string memory name, string memory jurisdiction) {
        require(kycProviders[provider].isApproved, "Provider not approved");

        KYCProvider storage providerDetails = kycProviders[provider];
        return (providerDetails.name, providerDetails.jurisdiction);
    }
    
    /**
     * @dev Utility function to check if a KYC provider is approved.
     * @param provider Address of the KYC provider
     * @return isApproved Boolean indicating if the provider is approved
     */
    function isApprovedProvider(address provider) external view returns (bool isApproved) {
        return kycProviders[provider].isApproved;
    }
}

This library includes several essential features:

  • Allows authorized entities to add approved KYC providers with specific details like name and jurisdiction.

  • Enables these KYC providers to verify users' identities and record the verification details.

  • Provides a method to check if a user is verified, including the verification timestamp and the provider who performed the verification.

  • Allows retrieval of details about approved KYC providers.

  • Includes a utility function to check if a KYC provider is approved.

Example of Usage

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "./RWAFW/EvireIdentityVerificationLibrary.sol";

/**
 * @title RealEstateTokenization
 * @dev This smart contract facilitates the tokenization of real estate properties on the Evire blockchain.
 *      It integrates identity verification using the EvireIdentityVerificationLibrary to ensure compliant transactions.
 */
contract RealEstateTokenization {
    using EvireIdentityVerificationLibrary for address;

    // Struct to represent a real estate property
    struct Property {
        uint256 id;
        string name;
        string location;
        uint256 value;
        address owner;
    }

    // Mapping of property IDs to Property structs
    mapping(uint256 => Property) public properties;
    // Counter for generating unique property IDs
    uint256 private propertyCounter;

    // Event emitted when a new property is tokenized
    event PropertyTokenized(uint256 indexed id, string name, string location, uint256 value, address indexed owner);
    // Event emitted when a property ownership is transferred
    event PropertyTransferred(uint256 indexed id, address indexed from, address indexed to);

    // Modifier to check if the user is verified
    modifier onlyVerifiedUser(address user) {
        (bool isVerified,,) = user.isUserVerified();
        require(isVerified, "User is not verified");
        _;
    }

    /**
     * @dev Tokenizes a new real estate property.
     * @param name Name of the property
     * @param location Location of the property
     * @param value Value of the property
     */
    function tokenizeProperty(string memory name, string memory location, uint256 value) external onlyVerifiedUser(msg.sender) {
        propertyCounter++;
        uint256 propertyId = propertyCounter;

        properties[propertyId] = Property({
            id: propertyId,
            name: name,
            location: location,
            value: value,
            owner: msg.sender
        });

        emit PropertyTokenized(propertyId, name, location, value, msg.sender);
    }

    /**
     * @dev Transfers ownership of a property to another verified user.
     * @param propertyId ID of the property to transfer
     * @param newOwner Address of the new owner
     */
    function transferProperty(uint256 propertyId, address newOwner) external onlyVerifiedUser(newOwner) onlyVerifiedUser(msg.sender) {
        Property storage property = properties[propertyId];
        require(property.owner == msg.sender, "Only the owner can transfer the property");

        property.owner = newOwner;

        emit PropertyTransferred(propertyId, msg.sender, newOwner);
    }

    /**
     * @dev Gets the details of a property.
     * @param propertyId ID of the property
     * @return name, location, value, owner
     */
    function getPropertyDetails(uint256 propertyId) external view returns (string memory name, string memory location, uint256 value, address owner) {
        Property storage property = properties[propertyId];
        return (property.name, property.location, property.value, property.owner);
    }
}

Description of the Smart Contract

This smart contract, RealEstateTokenization, allows for the tokenization and management of real estate properties on the Evire blockchain. It leverages the EvireIdentityVerificationLibrary to ensure that only verified users can participate in the tokenization and transfer of properties.

Key functionalities include:

  • Allows verified users to tokenize new properties by providing property details like name, location, and value. Each property is assigned a unique ID.

  • Enables the transfer of property ownership between verified users, ensuring compliance and security.

  • Provides a method to retrieve the details of a specific property.

This contract demonstrates the integration and usage of the EvireIdentityVerificationLibrary to enhance security and regulatory compliance in real-world asset transactions.

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