PDF Password Cracker Professional edition allows to search for "owner" and "user" passwords with brute-force and dictionary attacks, effectively optimized for speed (however, don't expect to recover long passwords in a reasonable time with these attacks). In addition, it has Key search attack, which guarantees the decryption (regardless the password length and complexity) of PDF files that use 40-bit encryption (the attack takes about 3-4 days on fast CPU systems).

Easy to use
Drag and drop PDF files
Do NOT need Adobe Acrobat software
Support Windows 98, ME, NT, 2000, XP and 2003 Systems
Support PDF 1.6 (Acrobat 7.x) files, including 40-bit RC4 decryption, 128-bit RC4 decryption, compressed files and unencrypted metadata
Support Adobe Standard 40-bit Encryption and Adobe Advanced 128-bit Encryption
Recovers user password required to open the file
Brute-Force, or Dictionary attacks are used to recover the password
Additional user dictionaries support, case changes, multiple mistypes and other modifications for each dictionary word
Program automatically saves password search state and can resume after a stop or a crash
Patterns can be used to minimize search time if any part of the password is known
Non-English characters in passwords are supported