Cracking a Password-Protected PDF File

Introduction

Password-protected PDF documents can be cracked with little effort. Surfing the web unveils countless applications for PDFs password removal.

Common applications like DrPDF, GuaPDF, PDFCrack or ElcomSoft can be used to unlock secured PDF documents. However, these applications are mostly paid, or in certain circumstances, may disclose the PDF document confidential information.

Methods for PDF password recovery

A user password can be broken either with a dictionary attack, or a brute force attack. Let’s describe these two modes:

• Dictionary attack: It is a variant of the ...