JS TS module to encrypt and decrypt string with password, using AES, 256bit salt, and 128 bit init vector.

aes_password_string_encryption.ts

import crypto from "crypto"; // npm i crypto

/** Helper function to generate a random salt */
export function generateSalt(length: number = 32): string {
  return crypto.randomBytes(length).toString("hex");
}

/** Derive a key from a password and salt */
export function deriveKey(password: string, salt: string): Buffer {
  return crypto.pbkdf2Sync(password, salt, 100000, 32, "sha256");
}

/** Encrypt a string using AES, returns string "salt32:iv16:encrypted"*/
export function encryptString(str: string, password: string): string {
  const salt = generateSalt();
  const key = deriveKey(password, salt);
  const iv = crypto.randomBytes(16); // Initialization Vector
  const cipher = crypto.createCipheriv("aes-256-cbc", key, iv);
  let encrypted = cipher.update(str, "utf8", "hex");
  encrypted += cipher.final("hex");
  return `${salt}:${iv.toString("hex")}:${encrypted}`;
}

/** Decrypt a string using AES */
export function decryptString(str: string, password: string): string {
  const [salt, ivHex, encrypted] = str.split(":");
  const key = deriveKey(password, salt);
  const iv = Buffer.from(ivHex, "hex");
  const decipher = crypto.createDecipheriv("aes-256-cbc", key, iv);
  let decrypted = decipher.update(encrypted, "hex", "utf8");
  decrypted += decipher.final("utf8");
  return decrypted;
}