Brain fingerprinting is a technique that uses electroencephalography (EEG) to detect electrical brain activity associated with recognition of familiar stimuli. It presents targets, irrelevant stimuli, and probes to a subject and compares their brain responses. If probes elicit the same response as targets, it suggests the information is present in the subject's brain. An accuracy rate of 100% has been found in tests of the technique. It has potential applications in criminal investigations, terrorism investigations, medical research, and other fields. However, more research is still needed to validate its reliability for use as legal evidence.