PDF Encrypt software is a very flexible and powerful program, it allows you to encrypt (using standard 40-bit or 128-bit or AES encryption) existing PDFs, set permissions, add user and owner password. For example you can encrypt a PDF without allowing to print it. The button to print the file will be disabled in Acrobat Reader application, you can also encrypt a PDF to allow the user to read it only if he knows the correct password.
There two passwords you can apply to a PDF. The first is the owner password. Opening a PDF with this password will allow you full access to the PDF when a user password has been assigned as well. This means that even if printing was disabled you will still be able to print the PDF when using this password. No password will be prompted for when opening the PDF if you secure it with only an owner password. The second is the user password. Opening a PDF with this password will restrict you based on how the PDF was password protected (printing may be disabled, for instance).

PDF Encrypt Features
* Supports Adobe Standard 40-bit Encryption and Adobe Advanced 128-bit Encryption.
* Supports AES encryption.
* Password protect opening of the document.
* Supports user password and owner password.
* Prevent printing of the document.
* Prevent copying of text/graphics.
* Prevent changes to the document.
* Supports add printing, copying and changing permissions to an encrypted PDF file.
* It can simple to use like a batch application to set permissions to every PDF in your archive.
* Set the document title, subject, author, keywords, creator to the encrypted PDF file(s).
* Supports command line operation (for manual use or inclusion in scripts).
* Batch operation on many files from command line and windows version.
* Easy to use.
* Does NOT need Adobe Acrobat software.
* The speed of encryption is very fast.
* Supports PDF1.6 protocol (Acrobat 8.x).