NodeJS Encrypt / Decrypt files

index.js

const { readdir, readFile, writeFile } = require('fs/promises');
const {
  randomBytes,
  createCipheriv,
  createDecipheriv,
  createHash,
} = require('crypto');
const { join } = require('path');

/**
 * Encrypts or decrypts all files in a directory using the specified algorithm and key
 * @param {string} dirPath - The path to the directory containing the files to encrypt or decrypt
 * @param {boolean} encrypt - A boolean indicating whether to encrypt (true) or decrypt (false) the files
 * @param {string} algorithm - The encryption algorithm to use
 * @param {Buffer} key - The encryption key to use
 */
async function encryptOrDecryptFiles(dirPath, encrypt, algorithm, key) {
  try {
    const files = await readdir(dirPath);

    // Loop through all files and encrypt or decrypt them
    for (const file of files) {
      const filePath = join(dirPath, file);

      // Read the file contents
      const data = await readFile(filePath);

      // Encrypt or decrypt the file contents
      const iv = encrypt ? randomBytes(16) : data.slice(0, 16);
      const dataToProcess = encrypt ? data : data.slice(16);
      const cipher = encrypt
        ? createCipheriv(algorithm, key, iv)
        : createDecipheriv(algorithm, key, iv);
      const processedData = Buffer.concat([
        cipher.update(dataToProcess),
        cipher.final(),
      ]);

      // Write the processed contents back to the file
      await writeFile(
        filePath,
        encrypt ? Buffer.concat([iv, processedData]) : processedData
      );

      console.log(
        `File ${file} ${encrypt ? 'encrypted' : 'decrypted'} successfully`
      );
    }
  } catch (err) {
    console.error(`Error processing files: ${err}`);
  }
}

const dirPath = join(__dirname, 'test_dir');
const shouldEncrypt = true;
const algorithm = 'aes-256-cbc';
const BASE_64_KEY = 'QDBLMXhGNl43MDU3';
const key = createHash('sha256')
  .update(String(BASE_64_KEY))
  .digest('base64')
  .substring(0, 32);

encryptOrDecryptFiles(dirPath, shouldEncrypt, algorithm, key);