assignment.js

const crypto = require('crypto');

// Personal information
const firstName = "Cletus";
const lastName = "Gizzo";

// 1. Create a Private Key and derive Public Key
const { privateKey, publicKey } = crypto.generateKeyPairSync('rsa', {
    modulusLength: 2048,
});

// 2. Generate an Address from the Public Key (simple hash of public key)
const publicKeyPem = publicKey.export({ type: 'pkcs1', format: 'pem' });
const address = crypto.createHash('sha256')
    .update(publicKeyPem)
    .digest('hex')
    .slice(0, 40);

// 3. Create a Message
const message = `My name is ${firstName} ${lastName}`;

// 4. Hash the message
const messageHash = crypto.createHash('sha256')
    .update(message)
    .digest('hex');

// 5. Create Digital Signature
const signer = crypto.createSign('sha256');
signer.update(message);
signer.end();
const signature = signer.sign(privateKey, 'hex');

// 6. Verify the signature
const verifier = crypto.createVerify('sha256');
verifier.update(message);
verifier.end();
const isVerified = verifier.verify(publicKey, signature, 'hex');

// 7. Display results
console.log('Private Key:', privateKey.export({ type: 'pkcs1', format: 'pem' }));
console.log('Public Key:', publicKeyPem);
console.log('Address:', address);
console.log('Message:', message);
console.log('Message Hash:', messageHash);
console.log('Digital Signature:', signature);
console.log('Signature Verification:', isVerified ? 'Valid' : 'Invalid');