Requirements
•Windows XP or higher
•About 6MB of disk space
•Enterprise edition: 4GB of disk space (for Thunder Tables)
Limitations
•PDF files protected using the Digital Rights Management (DRM) technology or third-party plugins such as FileOpen cannot be decrypted. If you try to start to decrypt such a file, APDFPR will display an error message:
•The brute-force attack is effective against short passwords only, generally up to 7 to 8 characters. Recovering longer password may take months or even years even on a very fast computer. In most cases, the dictionary attack helps discover the password, but if the password includes a combination of letters, digits and special chars, it cannot be recovered in reasonable time.
•If only the "owner" password is set, there is no need to recover it as the document can be decrypted instantly.
•Files protected with the "user" password and 40-bit encryption can be unlocked with the Key search attack.
•If you are having a trouble opening a damaged or corrupted file with APDFPR, try opening the file in Adobe Acrobat (the full version, not the Reader app) and saving a copy without making any changes. APDFPR can then be used on the copy of the file.