While other encryption programs let you protect numerous file types, this application only protects PDF files. PDF Encrypt & Decrypt has an orderly interface that neatly displays its list of options. The access controls to block or allow modifying, printing, or copying secured files are helpful. In our test, we easily encrypted files using separate passwords for the user and the owner. File protection proved steadfast, halting access without the correct password and quickly opening the file when the password was entered. This program supports only the PDF format, and will only process one file at a time, limiting its usefulness. Oddly, the Help file is for another program that includes PDF Encrypt & Decrypt as a feature rather than a standalone program. Nonetheless, this 15-day trial application is an effective tool for those simply aiming to lock PDFs.