Node.js crypto.privateDecrypt() Method

// Node.js program to demonstrate the 
// crypto.privateDecrypt() method

// Including the crypto and fs modules
const crypto = require('crypto');
const fs = require('fs');

// Reading the Public Key
pubK = fs.readFileSync('pub.key').toString();

// Passing the text to be encrypted using private key
const buf = Buffer.from('This is secret code', 'utf8');

// Encrypting the text
secretData = crypto.publicEncrypt(pubK, buf);

// Printing the encrypted text
console.log(secretData);

// Reading the Private key
privK = fs.readFileSync('priv.key').toString();

// Decrypting the text using public key
origData = crypto.privateDecrypt(privK, secretData);
console.log();

// Printing the original content
console.log(origData);

// Node.js program to demonstrate the
// crypto.privateDecrypt() method

// Including crypto and fs module
const crypto = require('crypto');
const fs = require("fs");

// Using a function generateKeyFiles
function generateKeyFiles() {

    const keyPair = crypto.generateKeyPairSync('rsa', {
        modulusLength: 530,
        publicKeyEncoding: {
            type: 'spki',
            format: 'pem'
        },
        privateKeyEncoding: {
            type: 'pkcs8',
            format: 'pem',
            cipher: 'aes-256-cbc',
            passphrase: ''
        }
    });

    // Creating public and private key file
    fs.writeFileSync("public_key", keyPair.publicKey);
    fs.writeFileSync("private_key", keyPair.privateKey);
}

// Generate keys
generateKeyFiles();

// Creating a function to encrypt string
function encryptString(plaintext, publicKeyFile) {
    const publicKey = fs.readFileSync(publicKeyFile, "utf8");

    // publicEncrypt() method with its parameters
    const encrypted = crypto.publicEncrypt(
        publicKey, Buffer.from(plaintext));

    return encrypted.toString("base64");
}

// Creating a function to decrypt string
function decryptString(ciphertext, privateKeyFile) {
    const privateKey = fs.readFileSync(privateKeyFile, "utf8");

    // privateDecrypt() method with its parameters
    const decrypted = crypto.privateDecrypt(
        {
            key: privateKey,
            passphrase: '',
        },
        Buffer.from(ciphertext, "base64")
    );

    return decrypted.toString("utf8");
}

// Defining a text to be encrypted
const plainText = "Geeks!";

// Defining encrypted text
const encrypted = encryptString(plainText, "./public_key");

// Prints plain text
console.log("Plaintext:", plainText);
console.log();

// Prints buffer of encrypted content
console.log("Encrypted Text: ", encrypted);
console.log();

// Prints buffer of decrypted content
console.log("Decrypted Text: ",
    decryptString(encrypted, "private_key"));