• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Chapter 3. Syntax > Encryption

3.5. Encryption

A PDF document can be encrypted (PDF 1.1) to protect its contents from unauthorized access. Encryption applies to all strings and streams in the document's PDF file, but not to other object types such as integers and boolean values, which are used primarily to convey information about the document's structure rather than its content. Leaving these values unencrypted allows random access to the objects within a document, whereas encrypting the strings and streams protects the document's substantive contents.

Note

When a PDF stream object (see Section 3.2.7, “Stream Objects”) refers to an external file, the stream's contents are not encrypted, since they are not part of the PDF file itself. However, if the contents of the stream are embedded within the PDF file (see Section 3.10.3, “Embedded File Streams”), they are encrypted like any other stream in the file. Beginning with PDF 1.5, embedded files may be encrypted in an otherwise unencrypted document (see Section 3.5.4, “Crypt Filters”).



PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint