[[!meta  title="Portable document format"]]

[PDF][] is a common format used to distribute content online, and
provides more of a "digital paper" feel than more flexible formats
like [[HTML]].  This determinism is why tools like [[LaTeX]] work well
with PDFs.  Unfortunately, the PDF specs have evolved over the years,
incorperating more of HTMLs "features" like JavaScript (PDF 1.3,
2000), and as the specs get more complicated, PDF readers get larger
and more complicated, and there are more possiblities for security
holes.

For a quick, quasi-technical introduction, see Didier Stevens's
articles on the [structure of PDF files][struct] and [malicious
variants][mal] as well as his list of [parsing tools][tools].  If you
want a bit more detail, Didier wrote up [a 23 page summary][book].


[PDF]: http://en.wikipedia.org/wiki/Portable_Document_Format
[struct]: http://blog.didierstevens.com/2008/04/09/quickpost-about-the-physical-and-logical-structure-of-pdf-files/
[mal]: http://blog.didierstevens.com/2008/04/29/pdf-let-me-count-the-ways/
[tools]: http://blog.didierstevens.com/programs/pdf-tools/
[book]: http://blog.didierstevens.com/2010/09/26/free-malicious-pdf-analysis-e-book/