Tailgating is very easy to spot. It’s when you follow someone through a barrier without swiping your entry card, adding your pin number etc. You might have seen someone do this in a car park or elsewhere, following another vehicle in without paying: it’s the same principle.
Taking its name from the Trojan Horse of ancient Greek tales, a Trojan is a form of malware in which the malicious code is hidden inside what looks like an innocuous application or other piece of code.
Two Factor Authentication / 2FA
2FA is becoming increasingly common, and is a really good idea for any accounts you may have where you have to enter bank or credit card details. Single (one) factor authentication is usually something your username and password.
With two factor, you’re normally asked either for your fingerprint (on iPhones for example), or you may be sent a code to your registered phone, which you need to enter after your password (PayPal operates like this). It’s really just an extra layer of security, based on something you know (eg your password) and something you have (a fingerprint or code from a mobile devices.