18 USC 2257 and CFR 75 are federal law requirements of record keeping of the proof of age of models and required notices on products including content.
This federal law places stringent record-keeping requirements on the producers of sexually explicit materials. The guidelines for enforcing these laws (colloquially known as 2257 Regulations (C.F.R. Part 75), part of the United States Code of Federal Regulations, require producers of sexually explicit material to obtain proof of age for every model they shoot, and retain those records. Federal inspectors may at any time launch inspections of these records and prosecute any infraction..
Regulations now permit third-party custodians, rather than producers themselves, to hold required records, and permit records to be maintained digitally. In addition, the updates permit the labeling requirement to be complied with through hyperlinks on Internet depictions.