challenge1.ts

import crypto from "crypto";

// Asymmetric encryption
const { publicKey, privateKey } = crypto.generateKeyPairSync("rsa", { modulusLength: 2048 });

// Encrypt
const plaintext = "This is a secret message.";
// TODO: Use the publicKey to encrypt the plaintext message. Remember that RSA encryption is public key encryption.
const encrypted = crypto.publicEncrypt(publicKey, Buffer.from(plaintext));

// Decrypt
// TODO: Use the privateKey to decrypt the encrypted message. The result should be the original plaintext.
const decrypted = crypto.privateDecrypt(privateKey, encrypted);

console.log("=Asymmetric encryption====================");
console.log("Original:", plaintext);
console.log("Encrypted:", encrypted.toString("hex"));
console.log("Decrypted:", decrypted.toString());
console.log("Verified:", plaintext === decrypted.toString());

// Create a digital signature
const sign = crypto.createSign("SHA256");
sign.update(plaintext);
sign.end();
// TODO: Use the privateKey to sign the plaintext message. This will generate a digital signature.
const signature = sign.sign(privateKey);

// Verify a digital signature
const verify = crypto.createVerify("SHA256");
verify.update(plaintext);
verify.end();
// TODO: Use the publicKey to verify the signature. It should return true if the signature is valid.
const isVerified = verify.verify(publicKey, signature);

console.log("=Digital signature========================");
console.log("Original:", plaintext);
console.log("Signature:", signature.toString("hex"));
console.log("Verified:", isVerified);