Adobe Acrobat 7 Professional - Manual (Page 27)

If you want to create a secure document
Acrobat provides several methods of applying security:
●
Use digital signatures to indicate approval of a PDF document or form that you filled out.
(See
Signing Adobe PDF documents .)
●
Certify documents to disallow subsequent changes. (See Certifying documents .)
●
Add passwords and set security options to restrict opening, editing, and printing PDF
documents. (See
Adding passwords and setting security options .)
●
Encrypt a document so that only a specified set of users have access to it. (See Encrypting
Adobe PDF files using certificates .)
●
Apply server-based security policies to PDF documents. Server-based security policies are
especially useful if you want others to have access to PDF documents only for a limited
time. (See
Encrypting Adobe PDF files using security policies .)
●
Apply the same security settings to a number of PDF documents by creating a custom
security policy. (See
Creating user security policies .)
●
Add security settings to PDF attachments, and use eEnvelopes. (See Using eEnvelopes to
send secure files .)