Use your 2FA codes ExpressVPN Keys Chrome extension How to enable 2FA on a website or app Important: You need to enable 2FA on a website or app for ExpressVPN Keys to generate 2FA codes. Similar to authentication apps like Authy, Keys can easily generate 2FA codes-also known as time-based one-time passwords (TOTPs)-for websites or apps with 2FA enabled. With Keys, you can add 2FA codes to compatible accounts on the ExpressVPN app for Android and iOS, and the ExpressVPN Key Chrome extension. Two-factor authentication (2FA) adds an extra layer of protection to your online accounts, preventing unauthorized access even if your passwords are compromised.