Physical keyloggers are often easy to detect. These are most often installed on public computers, such as those at your local library or in hotel lobbies, or office computers that are easily accessible to other employees within the company (anyone can sneak into your cubicle while you’re not around). Before you work at this type of machine, follow the cord that runs from the keyboard to the computer. If there is anything between the cord and the plug, let someone know and don’t use that machine. If it’s a wireless keyboard, avoid using the computer for any secure transactions.