did.js

// did/did.js

const crypto = require('crypto');
const { createHash } = require('crypto');

class DID {
    constructor(method = 'example') {
        this.method = method;
    }

    // Generate a new DID
    generateDID() {
        const id = `did:${this.method}:${this.generateUniqueId()}`;
        return id;
    }

    // Generate a unique identifier
    generateUniqueId() {
        return crypto.randomBytes(16).toString('hex');
    }

    // Resolve a DID to get its document
    async resolve(did) {
        // In a real implementation, this would query a DID registry or blockchain
        // Here we return a mock DID document for demonstration
        return {
            "@context": "https://www.w3.org/ns/did/v1",
            id: did,
            publicKey: [{
                id: `${did}#keys-1`,
                type: "Ed25519VerificationKey2018",
                controller: did,
                publicKeyBase58: this.generateUniqueId() // Mock public key
            }],
            authentication: [`${did}#keys-1`],
        };
    }

    // Sign a message with a private key (mock implementation)
    signMessage(message, privateKey) {
        const sign = crypto.createSign('SHA256');
        sign.update(message);
        sign.end();
        return sign.sign(privateKey, 'hex');
    }

    // Verify a signed message
    verifyMessage(message, signature, publicKey) {
        const verify = crypto.createVerify('SHA256');
        verify.update(message);
        verify.end();
        return verify.verify(publicKey, signature, 'hex');
    }
}

module.exports = DID;