Losing the password to an encrypted PDF can be frustrating. Luckily, PDF Password by Thegrideon Software can help you quickly and easily recover it.

The application was designed to recover PDF passwords from documents encrypted using 40 - 128 bit RC4 or 128 - 256 bit AES. It also features support for up to 64 simultaneous CPU or GPU processing threads and NVIDIA, AMD, and Intel HD Graphics GPUs.

The program is easy to install, configure and use. In order to begin a recovery attempt, users can navigate to and select the file they wish to decrypt. If the password is known and they simply wish to remove the PDF's permissions (print, copy, modify, add annotations, etc), users can click Save Unprotected File in order to create such a copy of the document.

To recover a lost password, users can queue several customizable dictionary, brute-force or mixed attacks. Mixed attacks can contain fixed, brute-force and dictionary elements. For example if part of the password is known, that part can be configured as the attack's fixed element and the unknown parts can be submitted to a brute-force attack, a dictionary one, or both.

Brute-force attacks can be customized in terms of which characters to use, while dictionary ones provide more options. One can select which word-list to use and its encoding, as well as whether to reverse words from the dictionary, change their case or capitalization or to replace letters with similar numbers (for example, O and 0).

As mentioned before this software solution features support for up to 64 simultaneous CPU or GPU processing threads and NVIDIA, AMD, and Intel HD Graphics GPUs.

Users can view available GPUs and configure the number of CPU based processing threads, as well as the progress and status of each of the queued attacks by accessing the dedicated tabs of the Starting password recovery window.

This software solution provides users with a fast, reliable and easy to use way of recovering PDF passwords or removing security permissions.