DID Registry Smart Contract | IDA — Identity for the AI Age

The DID Registry is the core on-chain contract that stores DID registrations, document hashes, and lifecycle state on the ADI blockchain.

Contract Address

Network	Address
ADI Mainnet	`0x...` (TBD)
ADI Testnet	`0x5FbDB2315678afecb367f032d93F642f64180aa3`
Local Devnet	Deployed via `forge script`

Interface

1 // SPDX-License-Identifier: MIT
2 pragma solidity ^0.8.24;
3 
4 interface IDIDRegistry {
5     struct DIDRecord {
6         address owner;
7         bytes32 documentHash;
8         string storageUri;
9         uint256 versionId;
10         uint256 created;
11         uint256 updated;
12         bool deactivated;
13         uint256 nonce;
14     }
15 
16     event DIDRegistered(string indexed did, address indexed owner, bytes32 documentHash);
17     event DIDUpdated(string indexed did, bytes32 newDocumentHash, uint256 versionId);
18     event DIDDeactivated(string indexed did);
19     event DIDOwnerChanged(string indexed did, address indexed newOwner);
20 
21     function registerDID(
22         string calldata did,
23         bytes32 documentHash,
24         string calldata storageUri
25     ) external;
26 
27     function resolveDID(string calldata did) external view returns (DIDRecord memory);
28 
29     function updateDID(
30         string calldata did,
31         bytes32 newDocumentHash,
32         string calldata newStorageUri
33     ) external;
34 
35     function deactivateDID(string calldata did) external;
36 
37     function changeOwner(string calldata did, address newOwner) external;
38 
39     function getNonce(string calldata did) external view returns (uint256);
40 
41     function isActive(string calldata did) external view returns (bool);
42 }

Key Functions

registerDID

Registers a new DID on the blockchain.

1 function registerDID(
2     string calldata did,
3     bytes32 documentHash,
4     string calldata storageUri
5 ) external;

Parameter	Type	Description
`did`	string	The full DID string (e.g., `did:adi:3f7a...`)
`documentHash`	bytes32	SHA-256 hash of the DID Document
`storageUri`	string	IPFS URI for the full DID Document

Requirements:

DID must not already exist
msg.sender becomes the owner
Emits DIDRegistered event

resolveDID

Returns the on-chain record for a DID.

1 function resolveDID(string calldata did) external view returns (DIDRecord memory);

Returns: Full DIDRecord struct including document hash, storage URI, version, and status.

updateDID

Updates the DID Document hash and storage URI.

1 function updateDID(
2     string calldata did,
3     bytes32 newDocumentHash,
4     string calldata newStorageUri
5 ) external;

Requirements:

msg.sender must be the DID owner
DID must not be deactivated
Increments versionId
Emits DIDUpdated event

deactivateDID

Permanently deactivates a DID.

1 function deactivateDID(string calldata did) external;

Requirements:

msg.sender must be the DID owner
DID must not already be deactivated
Sets deactivated = true
Emits DIDDeactivated event

Interaction Examples

Register a DID (ethers.js)

1 import { ethers } from 'ethers';
2 
3 const registry = new ethers.Contract(DID_REGISTRY_ADDRESS, DID_REGISTRY_ABI, signer);
4 
5 const did = 'did:adi:3f7a9b2e1c4d5f6a8b0c2d4e6f8a0b2c...';
6 const documentHash = ethers.keccak256(ethers.toUtf8Bytes(JSON.stringify(didDocument)));
7 const storageUri = 'ipfs://QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1mXWo6uco';
8 
9 const tx = await registry.registerDID(did, documentHash, storageUri);
10 await tx.wait();
11 console.log('DID registered:', tx.hash);

Resolve a DID

1 const record = await registry.resolveDID('did:adi:3f7a9b2e1c4d...');
2 console.log('Owner:', record.owner);
3 console.log('Document hash:', record.documentHash);
4 console.log('Storage URI:', record.storageUri);
5 console.log('Version:', record.versionId.toString());
6 console.log('Active:', !record.deactivated);

Gas Costs

Operation	Estimated Gas	Estimated Cost (ADI)
registerDID	~150,000	~0.003 ADI
resolveDID	0 (view)	Free
updateDID	~80,000	~0.0016 ADI
deactivateDID	~50,000	~0.001 ADI
changeOwner	~45,000	~0.0009 ADI

Security Considerations

Only the DID owner can update or deactivate their DID
Deactivation is permanent and irreversible
The contract uses a nonce-based replay protection
All state changes emit events for off-chain indexing
The contract is upgradeable via a proxy pattern for bug fixes