Blacklist implementation


i have a document management system in which i want to implement blacklist, which blocks users from uploading companies confidential documents when they try to upload. All the files will be uploaded from individual users from their desktop so its not done by admin. The documents can be anything (CAD files, images, word docs etc). I don’t want to block them on file extension basis, on file size basis and using any content search as i know all these can be bypassed. I need some effective logic to implement this which cannot be bypassed easily by at least 80% users…:slight_smile: