Underpass is a chat and file transfer application that features end-to-end encryption for complete privacy and security. Underpass is different from every other encrypted chat app because it does not use a third-party service. It's just two devices and a password. You can chat securely over the Internet or on a LAN, such as in an office, school, coffee shop, or home. All of your data is encrypted before it's sent over the network, and it can't be decrypted except by the other device using Underpass.