This program (Advanced PDF Password Recovery, or APDFPR) is intended to decrypt password-protected and restricted Adobe Acrobat PDF files, which have "user" password set (required to open/view the file), and/or "owner" password (when the file is only protected from editing, printing etc), i.e. remove the protection and/or break the PDF password. Restricted files are being unprotected instantly, while decryption of files with "open" password may be time-consuming. The program is also able to convert Kinkos Document Format (KDF) files to PDF files (without any protection).
Three versions (editions) are available: Standard, Professional and Enterprise.
Standard: basic edition of the program, that is only able to remove restrictions (from printing, selecting text and graphics and copying them into the Clipboard, adding/changing annotations and form fields). Does not handle PDF files with "open" password set, if that password is not known.
Professional: this edition has all functionality of the Standard one, but also allows to search for "owner" and "user" passwords with brute-force and dictionary attacks, effectively optimized for speed. In addition, it has the "Key search attack", which guarantees the decryption (regardless the password length and complexity) of PDF files that use 40-bit encryption. This attack takes from a few days (on modern dual-core systems) up to two weeks (on slow computers).
Enteprise: based on Professional edition, this one has an improved "Key search attack" using state-of-the-art "time-memory trade-off" technology, allowing to break "user" password (for 40-bit encryption) in just a few minutes (instead of days, as in Professional edition), using special pre-computed tables on DVD, shipped with express mail.
Version 3.10 includes command line for batch processing, additional dictionaries (German and Russian), and fixes some bugs.