At first, you have to specify which PDF Documents to protect.
This can be done easily in many ways. Press the "Add File" button to add select one or more PDF Documents, or press the "Add Folder" button to select an entire Folder and add all the PDF Documents that are in this folder.
Alternatively, you can simply right click on the PDF Documents in Windows Explorer and select "Encrypt PDF" from the context menu. In order to do this, you should have checked the option "Integrate with Windows Explorer" during the installation.
Another easy way to add PDF Documents is to drag and drop them on the application window.
After having selected which PDF Documents to protect, you have to choose the user password that is required for opening the PDF documents and the owner password that is required for the various permissions regarding the PDF Documents such as content copying, high-resolution printing, modifying e.t.c.
You can also specify to password protect pdf using 128bits or 40bits encryption.
Also, it is possible to set the document information and metadata by pressing the "Document Info" button and specifying there the author, subject, title, and keywords of the PDF documents.
After having done that, press the "Protect" button to batch password protect pdf files instantly.
In the end, Windows Explorer will open automatically with the protected documents having being selected.
It is also possible to specify the output folder of the protected PDF Documents. If it is selected to be the same as the documents folder then the protected document will have the same filename as the original document but will end with "_protected.pdf". If another folder is specified then the protected pdf document will have the same filename as the original one.
You can also choose to overwrite the original documents or to create the protected PDF documents in a subfolder of their original folder.
For example, you can specify to create them in a subfolder "protected". Free PDF Protector 4dots remembers your last five output folder options.
You can also import a list of document to password protect pdf.
To do so, create a text file listing all PDF files to be protected, one PDF file or folder on each line.
If your PDF file or folder requires a user password (for opening) write in a line the PDF file or folder and a comma and the password.
For example :
Read here command line usage
When the application is first started it asks you for your desired user interface language.
You can also change the user interface language from the "Language" menu.