Adobe InDesign CS4 - Manual (Page 516)

508 USING INDESIGN CS4
PDF
Adding security to PDF files
When saving as PDF, you can add password protection and security restrictions, limiting not only who can open the
file, but also who can copy or extract contents, print the document, and more.
A PDF file can require passwords to open a document (document open password) and to change security settings
(permissions password). If you set any security restrictions in your file, you should set both passwords; otherwise,
anyone who opens the file could remove the restrictions. If a file is opened with a permissions password, the security
restrictions are temporarily disabled.
The RC4 method of security from RSA Corporation is used to password-protect PDF files. Depending on the
Compatibility setting (in the General category), the encryption level will be high or low.
Note: Adobe PDF presets don’t support passwords and security settings. If you select passwords and security settings in
the Export Adobe PDF dialog box, and then click Save Preset, the passwords and security settings won’t be preserved.
Security options for PDFs
You can set the following options when you create a PDF or when you apply password protection to a PDF. Options
vary depending on the Compatibility setting. Security options are not available for PDF/X standards or presets.
Compatibility Sets the type of encryption for opening a password-protected document. The Acrobat 4 (PDF 1.3)
option uses a low encryption level (40-bit RC4), while the other options use a high encryption level (128-bit RC4 or
AES).
Be aware that anyone using an earlier version of Acrobat cannot open a PDF document with a higher compatibility
setting. For example, if you select the Acrobat 7 (PDF 1.6) option, the document cannot be opened in Acrobat 6.0 or
earlier.
Require A Password To Open The Document Select this option to require users to type the password you specify to
open the document.
Document Open Password Specify the password that users must type to open the PDF file.
Note: If you forget a password, there is no way to recover it from the document. It’s a good idea to store passwords in a
separate secure location in case you forget them.
Use A Password To Restrict Printing, Editing And Other Tasks Restricts access to the PDF file’s security settings. If the
file is opened in Adobe Acrobat, the user can view the file but must enter the specified Permissions password in order
to change the file’s Security and Permissions settings. If the file is opened in Illustrator, Adobe Photoshop, or Adobe
InDesign, the user must enter the Permissions password, since it is not possible to open the file in a view-only mode.
Permissions Password Specify a password that is required to change the permissions settings. This option is available
only if the previous option is selected.
Printing Allowed Specifies the level of printing that users are allowed for the PDF document.
• None Prevents users from printing the document.
• Low Resolution (150 dpi) Lets users print at no higher than 150-dpi resolution. Printing may be slower because
each page is printed as a bitmap image. This option is available only if the Compatibility option is set to Acrobat 5 (PDF
1.4) or later.
• High Resolution Lets users print at any resolution, directing high-quality vector output to Adobe PostScript and
other printers that support advanced high-quality printing features.
Updated 18 June 2009