PDF

According to Wikipedia, retrieved 16:24, 14 September 2011 (CEST), “Portable Document Format (PDF) is an open standard for document exchange. This file format created by Adobe Systems in 1993 is used for representing documents in a manner independent of application software, hardware, and operating systems.[2] Each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, graphics, and other information needed to display it.”

Security and usage rights[edit | edit source]

A PDF file may be encrypted for security, or digitally signed for authentication.

Various usage rights, can be included, e.g.

• The ability to edit
• the ability to save a PDF document along with annoations or filled-in forms

There exist software for password removal both commercial and free, e.g. pdfcrack under Linux. It takes a long time to break if you don't have a clue what kind of password you used

sudo aptitude install pdfcrack

Example that would permutate assci letters starting at words of 5 letters.

pdfcrack -f test.pdf -n 4 -c abcdefghijklmnopqrstuvwxyz

Links[edit | edit source]

Overviews[edit | edit source]

• Portable Document Format (Wikipedia)

Software[edit | edit source]

Viewers

• Adobe Acrobat Reader
• (Some) ebook tools and readers, e.g. calibre
• Ghostview (?)
• evince (PDF/PS viewer, default Ubuntu client ?)
• xpdf-reader

web services

• PDF to HTML converter

Editors

• Adobe Acrobat Professional
• pdfedit (Linux)
• gpdftext (Linux, for writing e-books)

Password removal