The items and parameters available in the window are explained as follows:  

Enable Security  

Ticking this check box to enable Encryption Level and Passwords options. If you prefer to save the PDF file without password security, leave this check box cleared.  

Encryption Level  

The following options are available:  

•  Low 40-bit RC4 (Acrobat 3.x, 4.x)  

•  High 128-bit RC4 (Acrobat 5.x and above)  

Passwords  

Passwords required to open the document  

Ticking this check box to enable Disallow Users to options. Enter the desired passwords in the Password column.  

Password required to change permissions and/or passwords  

Ticking this check box to enable Disallow Users to options. Enter the desired passwords in the Password column.  

Disallow Users to  

Print the document  

Ticking this check box to disallow users to print the document.  

Copy texts and images  

Ticking this check box to disallow users to copy the texts and images.  

Modify the document  

Ticking this check box to disallow users to modify the document.  

Modify comments  

Ticking this check box to disallow users to modify comments.  

Enhanced Permissions (128-bit)  

You may adjust the settings only when you set the Encryption Level at High 128-bit RC4 (Acrobat 5.x and above).  

Allow printing in low resolution  

Ticking this check box to allow users to print the document in low resolution.  

Allow screen readers  

Ticking this check box to allow users to read the document on screen.  

Allow filling in form fields  

Ticking this check box to allow users to fill in the form fields.  

Allow changes to the assembly  

Ticking this check box to allow users to change the assembly.