Click Tools menu Options.At the command prompt,
enter options.
In the Options dialog
box, Open and Save tab, click Security Options.
In the Security Options
dialog box, Password tab, enter a password.
To encrypt drawing
properties, such as the title, author, subject, and keywords, click
Encrypt Drawing Properties.
Click OK.
In the Confirm Password
dialog box, enter the password you used. Click OK.
WarningIf
you lose a password, it is not recoverable. Before you add a password
to a drawing, you should create a backup that is not protected with a
password.