AEM offers various capabilities for managing and securing digital assets, including PDFs. However, for specific functionalities like securing PDFs in a way that they can only be decrypted by connecting to your server, you would typically need to integrate AEM with Adobe's Digital Rights Management (DRM) solutions or other third-party DRM solutions.
Adobe's DRM solutions, part of the Adobe Experience Cloud, can provide robust security for PDF documents, ensuring they can only be opened by authorized users under specific conditions. This might involve setting up a license server that authenticates and authorizes access to the secured content.