Adobe acrobat reader 7.0 User Manual

 

Acrobat security is similar to home security. Just as people lock their doors to prevent 
others from entering their houses without permission, authors may use the various Acrobat 
security features to "lock" PDF documents. For example, authors can add passwords to 
restrict users from opening a PDF document, and they can prevent users from printing or 
editing a document. They can also use digital signatures to certify and encrypt PDF 
documents. A document to which security features have been applied is called a restricted 
document. 

PDF files can take advantage of the security features of Windows XP and a number of 
other security systems:

●     

Password-protected documents. When you receive a restricted PDF document, you may 
need to enter a password to open it.

●     

Restrictions against copying or printing. Some restricted or certified documents do not 
require a password but still prevent you from copying information or printing the file.

●     

Encrypted documents. If a document is encrypted, you may not be able to open it without 
permission from the person who created the document. Documents with special security 
policies applied may require you to log in to a server to open the document. If you're 
having trouble opening a PDF document, or if you're restricted from using certain 
features, contact the PDF document author. 

●     

Digital signatures. If the PDF document contains additional usage rights, you may be 
asked to sign or approve a PDF document. (See 

.)

●     

Documents to which a server-based security policy has been applied. (See