Advanced PDF Password Recovery Software to decrypt protected Adobe Acrobat PDF files (with standard security handler or FileOpen plug-in). Decryption is performed instantly and can operate in a batch mode. http://www.elcomsoft.com/apdfpr.html

FileOpen Systems Inc. A plugin to Adobe Acrobat that helps ensure that a digital publication is not redistributed or uploaded to another website. http://www.fileopen.com/

Guaranteed Pdf Decryptor A utility to decrypt any password-protected PDF files with guarantee, regardless of password used. Demo available. http://www.password-crackers.com/crack/guapdf.html

Kyler Laird's PDF utilities Provides tips on removing security protections from files. http://www.ecn.purdue.edu/~laird/PDF/

ITEKSOFT eDocPrinter and eDocProcessor applications, that encrypt and print PDF, optimizing it beforehand. http://pdf.iteksoft.com/

Digital Delivery Secure electronic software and information distribution. Prevents unauthorised reading and copying of files. Evaluation version available. http://www.trusted-time.com/

Datafarm Inc. Developers of Acrobat Plug-ins and other PDF tools. http://www.datafarminc.com/