An identity tape is a data tape with identification data used by Federation citizens during the 23rd century. Identity tapes were typically used by citizens engaged in deep-space travel that might take them out of regular contact with the Federation. The tapes provided a form of verification and guarded against identity fraud over long periods of absence from society, during which time their identity might be assumed by another individual. Identity tapes included biometrics of the individual and could be matched to records of that individual maintained in the computer of a starship or starbase.
The Vendorian posing as Carter Winston supplied the real Carter Winston's identity tapes to Spock according to Starfleet regulations when his vessel was discovered by the USS Enterprise after he had been missing for five years. (TAS: "The Survivor")