Encrypting Multiple pdf Files Within a Folder

NOTE: If your folder contains files that are not in the .pdf format, this process will automatically attempt to convert those files into pdf files. For example, if you have an image file with a .jpg format, or a word file, adobe acrobat will attempt to convert those files into .pdf files before encrypting them. It is recommended that your encryption folder contain only pdf files that you want encrypted.

Open Adobe Acrobat Pro.
Select the 'Tools' tab
Open the 'Action Wizard' tool.
Next, select 'New Action' on the Action Wizard toolbar.
Under 'Choose tools to add' select the 'Protection' drop down menu and double-click on 'Encryption' This will add the encryption option on the right side panel.
Make sure the 'Prompt User' check box is NOT checked and click 'Specify Settings'.
Select 'Password Security' in the drop down menu and specify your encryption settings - then click ok – you will be prompted to verify the passwords you’ve created.
Close the 'document security' window.
Next, under the right side panel of the 'create new action' window - click on the folder icon under 'files to be processed' then browse to the folder containing the pdf’s you want to protect and select it – then click 'ok'.
Click Save – you will be prompted to name the action. You can call it something like 'Encrypt Folder' - You can also write a description if you choose.Then click save.
Open Adobe Acrobat Pro and select the Action Wizard under the tools panel.
Look for the 'Encrypt Folder' action that you created under the 'Action List' on the right side panel and click on it – you should notice that a list of the files contained in your pdf folder is displayed.
Press the blue start button – you will notice that as the settings are applied to each file they will have a check mark next to them. Once the process is complete the blue 'start' button will say 'completed'.