Device fingerprinting is the technique of identifying a phone, tablet or computer by combining many small technical details about it, such as its operating system, browser version, screen size, language, time zone, fonts and graphics hardware. The combined result, called a device or browser fingerprint, is often distinctive enough to recognise the same device on a later visit without storing anything on it. How fingerprints are built and used is explained in full in the Digital Fingerprint entry.
Banks, payment firms and online shops use device fingerprinting for fraud detection. A login from a device never seen on an account, or the same device opening dozens of new accounts, is a common warning sign of account takeover or fake sign-ups. It is usually combined with behavioral analytics, which look at how someone types or moves rather than what device they use.
Because a fingerprint can track people across websites without their knowledge, European data protection authorities have said that fingerprinting can require the same consent as cookies unless it is strictly necessary, for example for security. Fraudsters, in turn, try to defeat it with tools that fake or randomise device details.