My undergrad university library has (had?) a bound copy of PGP source code on the stacks for checkout. If I remember correctly, digital copies of the binaries

My undergrad university library has (had?) a bound copy of PGP source code on the stacks for checkout. If I remember correctly, digital copies of the binaries and source code were prohibited for export as a munition, but publishing the source code in a book, made it a book, and thus eligible for export.