covered periodmeans the period beginning on the date on which an individual is convicted of a violation of section 2423 of title 18 and ending on the later of—
imprisonmentmeans being confined in or otherwise restricted to a jail, prison, half-way house, treatment facility, or another institution, on a full or part-time basis, pursuant to the sentence imposed as the result of a criminal conviction.
passportmeans a passport book or passport card.
unique identifiermeans any visual designation affixed to a conspicuous location on the passport indicating that the individual is a covered sex offender;