DeviceTrustChain

Secure IoT Data Trust Framework
Linking IoT Device Data to Versioned NFTs with Private IPFS Storage and On-Chain Integrity Verification

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📜 Overview

This project establishes a trustless framework where IoT device data is:

1. Stored off-chain on a self-hosted private IPFS network.
2. Linked to versioned ERC721 NFTs (one per transaction) with on-chain integrity proofs.
3. Verifiable by third parties via cryptographic hashes.

Key Innovation: Allows multiple entries (NFTs) per deviceId while enforcing uniqueness via transactionId.

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🚀 Core Features

1. NFT Management

• ERC721 NFTs: Each represents a unique IoT data transaction.
• Versioned Metadata:
  • deviceId: IoT device identifier (non-unique).
  • transactionId: Unique identifier for the data transaction.
  • ipfsCID: Private IPFS Content Identifier for JSON data.
  • dataHash: SHA-256 hash of the JSON data.
  • version: Tracks updates to the same token.

2. Security & Access

• Role-Based Access Control: Restrict minting/updates to authorized roles.
• Private IPFS: Self-hosted cluster with swarm keys and access controls.
• Tamper-Proof Verification: On-chain hash comparison for data integrity.

3. Workflow Automation

• Minting & Updates: Scripts for NFT creation and metadata versioning.
• Event Logging: DeviceMinted and DeviceDataUpdated for off-chain tracking.

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📦 Smart Contract

Contract: IoTDeviceNFT.sol

Tech Stack:

• Solidity ^0.8.19
• OpenZeppelin (ERC721URIStorage, AccessControl, Counters)

Key Functions:

Function	Description	Access Control
mintDeviceNFT()	Mints NFT with deviceId, transactionId, and hashes.	MINTER_ROLE
updateDeviceData()	Updates IPFS CID and hash for a token.	MINTER_ROLE
verifyData()	Returns true if proposed hash matches stored hash.	Public

Snippet:

function mintDeviceNFT(
    address to,
    string memory deviceId,
    string memory transactionId,
    string memory ipfsCID,
    bytes32 dataHash
) external onlyRole(MINTER_ROLE) {
    require(!_usedTransactionIds[transactionId], "Duplicate transactionId");
    _tokenIds.increment();
    uint256 newTokenId = _tokenIds.current();
    _tokenData[newTokenId] = DeviceData(deviceId, transactionId, ipfsCID, dataHash, 1);
    _usedTransactionIds[transactionId] = true;
    emit DeviceMinted(newTokenId, deviceId, transactionId, ipfsCID, dataHash);
}