The content in the PDF may be private and you don't want other people to see it. The information contained in the PDF is valuable, it could be a training course, bid file, healthcare record, price list or a consulting report. Any way, you don't want to lose them. Then just try to use this PDF Encryption program to add a password to protect your own PDF files.
For different situations, you may have different encryption needs in the daily life and work. So CoolMuster PDF Encrypter provide users with 3 levels of encryption system: 40 bit RC4, 128 bit RC4 and 128 bit AES.
Besides password and encryption level, there are also lots of other options for your reference, such as resolution settings, document printing, copying, etc. You're enabled to select all you wanted options with one click.
3 levels for encryption, batch set password, more personalized options to protect privacy of PDF and so on. It is the most outstanding application I've used!- Tina