Encrypt & Decrypt with Node's crypto lib.

test.js

const crypto = require("crypto");

crypto.generateKeyPair(
  "rsa",
  {
    modulusLength: 4096,
    publicKeyEncoding: {
      type: "spki",
      format: "pem"
    },
    privateKeyEncoding: {
      type: "pkcs8",
      format: "pem",
      cipher: "aes-256-cbc",
      passphrase: "temp"
    }
  },
  (err, publicKey, privateKey) => {
    // Handle errors and use the generated key pair.
    console.log(publicKey, privateKey);

    const user = "STRING_TO_ENCRYPT";

    const userTimeString = Buffer.from(user, "utf8");
    const encryptedString = crypto.publicEncrypt(publicKey, userTimeString);

    // const encrypted = Buffer.from(encryptedString, 'utf-8');
    const decryptedString = crypto.privateDecrypt(
      {
        key: privateKey.toString(),
        passphrase: "temp"
      },
      encryptedString
    );

    console.log(Buffer.from(encryptedString).toString("base64"));
    console.log(decryptedString.toString("utf8"));
  }
);