Can a public share link or direct download link be 'hacked' to see other files in folder?

Hi there,

 

We have sensitive files that we'd like to share individually with clients via a direct download link (https://...dl.dropboxusercontent.com/...). Unfortunately, we're unable to share the files via any other method due to how our business systems currently work. Our clients are NOT members of our Dropbox folder - we don't want them to be able to see any file other than ones we explicitly link to them.

 

First, we had to turn off the 'Link restrictions' setting which typically prevents non-members from accessing the folder (and the files within it) via a link. Does this make our Dropbox any more likely to be 'hacked' by anyone acting maliciously?

 

 

Second, is the direct download link (https://...dl.dropboxusercontent.com/...) secure so that no client nor any member of public can manipulate the link to view other files within parent folder(s) or even view the directory of files?