What type of authentication uses physical devices to verify identity?

The correct answer is tokens, which are a type of authentication that relies on physical devices to verify identity. Tokens can take various forms, such as smart cards, key fobs, or USB devices. These devices generate unique codes or contain embedded credentials that users must present in conjunction with their user credentials (like a password) to gain access to systems or data.

The use of tokens enhances security by providing something that the user has (the physical device), creating a two-factor authentication environment when combined with something the user knows. This means even if a password is compromised, unauthorized access is still thwarted without the corresponding token.

In contrast, biometrics involve the use of unique physical characteristics (such as fingerprints or facial recognition) for identity verification, rather than relying specifically on a physical device that generates a token. Digital signatures are cryptographic methods used to validate the authenticity and integrity of a message or document, rather than a form of identity verification through physical means. Context-aware authentication takes into account various contextual factors (like location and device) to assess whether to grant access, rather than relying solely on physical tokens for verification.