If you think that the computer that you are using is not trustworthy, for example when using a public computer in a library, everything that you type might be recorded by a hardware keylogger.

You can use the Florence virtual keyboard to protect you against a hardware keylogger when typing passwords and sensitive text. To display the virtual keyboard, click on the keyboard icon in the notification area.

There is currently no virtual keyboard in Tails Greeter, so a hardware keylogger could record your persistent volume passphrase or administration password.