The computer might be compromised if its physical components have been altered.For example, if a keylogger has been physically installed on the computer, your passwords, personal information, and other data typed on the keyboard could be stored and accessed by someone else, even if you are using Tails.
Use a [[password manager|doc/encryption_and_privacy/manage_passwords]] to paste saved passwords. This way, you don't have to type passwords that might be visible to people or cameras near you.
Use the [[screen keyboard|doc/first_steps/accessibility#keyboard]], if you are using a public computeror worry that the computer might have a keylogger.
Keyloggers are easy to buy and hide on desktop computers but not on laptops. For an example, see <a href="https://www.youtube.com/watch?v=6JJo8qCYE8M">KeeLog: KeyGrabber forensic keylogger getting started</a>.
Other hardware alterations are much more complicated and expensive to install. For an example, see <a href="https://arstechnica.com/tech-policy/2014/05/photos-of-an-nsa-upgrade-factory-show-cisco-router-getting-implant/">Ars Technica: Photos of an NSA “upgrade” factory show Cisco router getting implant</a>.
Firmware includes the BIOSorUEFIand other software stored in electronic chips on the computer.All operating systems, including Tails, depend on firmware to start and run, so no operating system can protect against a firmware attack. In the same way that a car depends on the quality of the road it is driving on, operating systems depend on their firmware.