Digify

Send important files to your contacts with the reassurance that they won't be able copy, share, or make greater use of them, thanks to Digify's self-destruct feature. With this tool, you can send any document, video, audio, or other file knowing that they have an expiration date and can't be duplicated (they can only be opened and read). Digify provides comprehensive security in also protecting your most important files on Dropbox, where you can set a longer period of time for storing them if necessary. It's worth noting that your classmates, friends, or co-workers also has to have Digify installed to access your doc. This completes the loop in terms of security, helping you feel reassured regarding your most important information. Lastly, the tool also includes an option to check who's viewed each document, when, and for how long. Thus if you want, you can immediately delete any file that's already been opened and read.