The TKey is a small computer in a USB-C form factor that can run small device applications which are loaded onto it. The purpose of TKey is to be a secure environment for applications that provide some kind of security function. Some examples of such security functions are:

• Time-based one-time password (TOTP) token generators
• Signing oracles
• Secure random numbers
• Encryption
• 2FA

There is no way of storing a device application (or any other data) on the TKey. A device app has to be loaded onto the TKey every time you plug it in.