Dropshare Safe is a free service provided for Dropshare for Mac and iOS. With Dropshare Safe, you're easily able to create access-restricted download URLs for your files uploaded with Dropshare.
You can specify a lifetime and optionally a password which is required to download the file - you can also track when and how often your file has been downloaded, and from which location.
Dropshare Safe acts as a so called proxy - it will never disclose the actual URL of the file. However, once you share the actual URL of the file people will of course be able to download the file without Dropshare Safe being involved, so make sure to keep the actual URL secret if you're using Dropshare Safe.