This provides a basic implementation of the W3C DID specification which was approved as a recommendation in late June 2022 Specification can be found on https://www.w3.org/TR/did-core/

MyDID implementation adopts the following format when generating DIDs

"did:ttd:"(namespace):identifier
namespace: idchar*
identifier: base58char+
idchar: ALPHA / DIGIT
base58char: 123456789ABCDEFGH JKLMN PQRSTUVWXYZabcdefghijk mnopqrstuvwxyz

e.g.

did:ttd:zkjhdj365dqbbtc28hic
did:ttd:sg:zkjhdj365dqbbtc28hic

#How to use

First you need to generate a key pair. General EC curves and edward curves are supported at the moment.

KeyPairGenerator generator = KeyPairGenerator.getInstance("EC");
//or
KeyPairGenerator generator = KeyPairGenerator.getInstance("EC", "BC");
//or
KeyPairGenerator generator = KeyPairGenerator.getInstance("Ed25519");
...
KeyPair keyPair = generator.generateKeyPair();

Then use the generated keypair to call the createDid method in the DidUtil class This will generate the DID and return its corresponding DIDDocument

DIDDocument didDoc = DidUtil.createDid(keyPair);
System.out.println(didDoc.getId().getFullQualifiedIdentifier());

Generated DID document can be stored in Algorand blockchain. For local testing Algorand sandbox, which is available on https://github.com/algorand/sandbox can be used for this. Clone the Algorand sandbox repo and start the sandbox using ./sandbox up command. This will start the Algorand private node on the local machine. Then create client to connect to the Algorand

AlgodClient algodClient = AlgorandUtil.createAlgodClient();

We need an Algorand account to store the DID document on the chain. By default, the sandbox comes with 3 accounts. I will get the first account.

KmdApi kmdApi = AlgorandUtil.createKmdApi();
String defaultWalletHandle = AlgorandUtil.AlgorandSandboxPrivateNode.getDefaultWalletHandle(kmdApi);
List<Address> walletAddresses = AlgorandUtil.getWalletAddresses(kmdApi, defaultWalletHandle);
byte[] sk = AlgorandUtil.getPrivateKeyFromWallet(kmdApi, walletAddresses.get(0), defaultWalletHandle, "");
Account steward = new Account(sk);

Then I use that account to store the document on the chain. JSON representation of the DIDDocument will be stored in the blockchain as

AlgorandUtil.storeDID(algodClient, steward, didDoc);

We can use the Algorand indexer client to retrieve any DIDDocument from the chain, if we know the DID To do that, first we need to create an Algorand Indexer client

IndexerClient indexerClient = AlgorandUtil.createIndexerClient();

Then we can use the AlgorandClient to retrieve the document as follows. You can use either a DID object or a string representation of (full qualified) DID

JSONObject documentSender = AlgorandUtil.getDIDDocument(indexerClient, didDoc.getId());