Recover PDF Passwords:
User (Open) Password and Owner (Restrictions) Password:
NOTE 1: There are two PDF password types - user (open) password and owner (restrictions) Password. The user password (also called open password) protects a PDF file from opening. The owner (restrictions) password sets certain restrictions (to protect a PDF file from printing, inserting, deleting, and extracting pages, entering form data, signing, creating template pages, etc.). A PDF file may either be not encrypted at all or encrypted either only by a user (open) password, only by an owner (restrictions) Password, or by both passwords.
NOTE 2: If the file is locked by both a user (open) password and an owner (restrictions) password, then recovering of the owner (restrictions) Password needs (and is accompanied by) recovering of the user (open) password. In contrast, recovering of a user (open) password does not need (and is not accompanied by) recovering of an owner (restrictions) Password. If an owner (restrictions) Password is significantly stronger than a user (open) password, recovering of only a user (open) password can be significantly faster than recovering of both passwords. Accordingly, if all you need is to recover a user (open) password (to open a PDF file), it is reasonable to recover a user (open) password only; however, if you need to recover both a user (open) password (to open the file) and an owner (restrictions) Password (to remove restrictions), use the algorithm presented on this page.
NOTE 3: Any encryption (including encryption by Adobe Acrobat full program) can (in certain cases) affect fonts, Javascript code, fields, and general file appearance. In such cases, a decryption (even by known password) may not restore the original (pre-encryption) fonts, Javascript, fields, and file appearance.
NOTE 4: Decryption by a known password usually affects neither fonts, nor Javascript code, nor fields, nor general file appearance. In contrast, decryption by removal of an unknown password can (in certain cases) affect Javascript code and fields, and thus can create a "mess". By this reason, in general, if the password is known, decryption should be done by using the known password rather than by removing a unknown password; if the password is unknown, it is reasonable to recover it (rather than to use the decryption by removal of an unknown password).
NOTE 5: The algorithm of this operation will detect and mark by a corresponding error message any input file that:
NOTE 7: The algorithm of this operation will accept and successfully process any file (other than listed above), even if the file is a PDF with a static XFA structure.