Persons subject to U.S. jurisdiction providing authorized carrier or travel services must retain for at least five years from the date of the transaction a certification from each customer indicating the provision of the CACR that authorizes the person to travel to Cuba. In the case of a customer traveling under a specific license, a copy of the license or the license number must be maintained on file. The names and addresses of individual travelers must also be maintained on file for at least five years. See 31 CFR § 515.572(b). This information, including certifications and copies of licenses or license numbers, may be collected and maintained in any form, including electronically.