一鍵破解PDF保護密碼！
http://www.techbang.com.tw/posts/4440-crack-pdf-password-protection-for-a-key
PDF Password Remover Tool
官方網站：http://www.pdf-technologies.com/pdf-library-password-recovery.aspx
下載網址：http://www.pdf-technologies.com/downloads/passwordrecovery.exe
PDFUnlock! - Unlock secured PDF files online for free.
http://www.pdfunlock.com/
