Why A-PDF Password Security
Encrypt PDF Files
Protect your PDF documents from unauthorized access with standard password security:
40-bit RC4 encryption, which is supported by Adobe Acrobat 3.0 or above.
128-bit RC4 encryption, which is supported by Adobe Acrobat Reader 5.0 or above.

Decrypt PDF Files
You can also remove the standard password security from protected PDF files. Supports 40/128 bit RC4 and 128 AES encryption.

Note: you may get a password prompt to open the file. If you have no idea what password is, the program can not find passwords automatically for you, you may find a PDF password cracker tool here.

Change Restrictions of PDF Files
With A-PDF Password Security, you can set a PDF file to require a password to open, and/or restrict access. For example, to allow or not allow printing, copying content, changing the file, etc.

Batch Change Properties of PDF Files
With A-PDF Password Security, you can batch edit and modify your PDFs metadata, such as PDF Title, Subject, Author and Keywords.

Add Expiry Time and Data to PDF Files
With A-PDF Password Security, you can set or remove expiration Time and Date on a PDF.

Password Pool
If you need unsecure a batch of PDF files with one password, you can special a password pool. A-PDF Password Security will try the passwords one by one, instead of input them manually.

Work with Hot Directories
You can set up a monitored directory, where all files written to that directory will be encrypted as they are saved. The original files can also be moved to a backup directory. All of the operations will be recorded in log files.

Home Page: http://www.a-pdf.com/security/password.htm