PDF is a file format for the long-term archiving of electronic documents. Portable Document Format (PDF) is created by Adobe Systems. PDF is used for representing two-dimensional documents in a manner independent of the application software, hardware, and operating system. Each PDF file encapsulates a complete description of a fixed-layout 2D document that includes the text, fonts, images, and 2D vector graphics which compose the documents.

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

The standard security provided by PDF consists of two different passwords: "user password" and "owner password". A PDF document may be protected by password to open ('user' password) and the document may also specify operations that should be restricted even when the document is decrypted: printing; copying text and graphics out of the document; modifying the document; and adding or modifying text notes and Acroform fields (using 'owner' password).