Self-Destructing or Time-Limited Files

[OverlayHunter]

From time to time in business, I have to send someone files, typically pdf and jpg. It is important that those files be limited in function to make them difficult to pass along to others. The receiving party typically needs them for 2 hours or less.

Is there a way to render the files useless after a certain amount of time?

For example, can they be automatically overwritten (thereby effectively deleting them) or rendered impossible to open after a given period of time?

Are there other methods to accomplish the goal I haven't thought of?

I've poked around the internet but I haven't found what I need.

Thank you for the assistance.

[headhawg]

The short answer is that it can be done, but probably not implemented in the way you want. Image files and PDFs need other programs to open them. In other words, they are not self-executable. The only solutions that I can think of are using a DRM company like Digify, or have some kind of custom .bat or .exe file "seek and destroy" the files you need deleted. If you are not a coder, then both solutions are expensive. And with the custom delete program, I am not sure that your clients would want to install it even if they could.

Another possibility could be storing the files in the cloud and restrict access to Read Only for a limited time period.

[JustRalph]

Where do they reside? Their own directory? On the customers hard drive/

You “send them”. What format email? USB drive ? Cd?

Found this via google

https://digify.com/blog/pdf-document...self-destruct/

We used to do this via dos back in the day

[Dave Schwartz]

Originally Posted by OverlayHunter

From time to time in business, I have to send someone files, typically pdf and jpg. It is important that those files be limited in function to make them difficult to pass along to others. The receiving party typically needs them for 2 hours or less.

Overlay,

Google's G-Suite has some of the capability and it could be made to work.

You can create a document in G-Suite and turn off the ability to:

* Save it (i.e. download it)
* Copy it to another folder (i.e. theirs)
* Select Text
* Convert to another file type.

You would have to manually control their access to the file. That is, in two hours (or whatever) you'd remove their access to the file.

My understanding is that this can only be accomplished with the pay-for version of G-Suite.

Now, the bad news... I do not know how to do this. Sorry.

Dave
PS: If you really need this, I can find the VA who coached me when I was trying to set something up in G-Suite. She was quite the expert. I bought 2 hours of her time for $80, as I recall.

[Jeff P]

Have you considered setting a password that expires at a predefined date/time?

A Google search for the phrase "encrypt file password expires at a predefined time" (without the quotes) turned up the following link:

Quick Crypt creates self-expiring encrypted files:
https://www.ghacks.net/2014/07/07/qu...crypted-files/

Here you find several interesting options:

1. Encrypt file using a system ID unique to the PC. Attempts to decrypt the file on other computer systems will result in errors even if the correct password is entered.
   
   
2. Set a file expiration date. The file cannot be decrypted anymore once the expiration date is reached.
   
   
3. Create a distributable zip file. This adds the Quick Crypt program and the encrypted file to a zip file for easy distribution since Quick Crypt is required to decrypt an archive.

FYI, I don't have any affiliation with, nor have I ever used, Quick Crypt.

However, reading the write up at the above link did spark some ideas.

I'm guessing the measures you decide to take ultimately depend on how important it is that your content be seen by intended viewers only and go nowhere from there.

That said, a few random thoughts --

Could a user get around an expired password simply by setting the date/time on a machine back to an older date/time? (For a lot of downloadable software the answer is actually yes.)

Some possibilities for dealing with that:

• Could you create your own web-based content delivery system? I think it's possible (through scripting and various server settings) to create a non-public facing web page that displays content (an image) in a manner whereby: The user must login to view the content, the image cannot be downloaded by normal webbrowser behavior, and the page can only be viewed by an authenticated user n number of times and/or before a predefined date/time. Of course this comes with an obvious built-in weakness: The user who wants to can probably do a screen capture or use video recording software to record the pixels displayed on the monitor.(Although many mouse-keyboard combinations can trapped for via scripting. Whether or not you decide to go this route may depend on how much you trust your users.)

Basically, you send the user a link. Verify that the user has viewed the page. And take the page down afterwards.

• Could you create your own client-based content delivery .exe file? Basically, you write your own source code (using whatever dev environment) and compile it as a downloadable .exe file which your user installs on a laptop or pc.

The user double clicks the .exe file to launch your app, logs into the app using a one time only password, and from there the app displays an image file (.bmp, .png, .jpg, etc.) that resides on your remote server (and not on the user's machine.)

And of course, when the user shuts down the app, code in the app's form_terminate() event (or equivalent) deletes (or scrambles) the .exe file itself... which short of extraordinary measures taken by your user pretty much ensures your user sees the content exactly once.


-jp

.

[OverlayHunter]

Headhawg, JR, Dave and Jeff, thank you, I sincerely appreciate all of the time you took and the helpful information you've provided. I am going to look into all of the ideas.

I don't have or need a website, cloud or email is what I was thinking for delivery but I have to look more carefully at your suggestions to see if I should more strongly consider other forms.

Headhawg, Read Only for a limited time sounds like a possibility that doesn't sound to,o complicated with the right cloud server.

JR and Headhawg, I'll look at Digify.

Dave, I'll look at G-Suite and if it looks practical, I'll ask for your VA's contact info.

Jeff, I actually stumbled onto Quick Crypt this morning but I didn't see all of the information you provided. I will look into that again, including your legitimate concern about changing date/time on the machine.

Again, thank you all.

[wilderness]

Have some vague recollection of some PDF files that expired after x-Date.
No clue if the current version of Acrobat (and/or Acrobat Distiller (print driver)) offer a date.time stamp in the Security Settings (the more than 20YO version I've does not).

[Tom]

This type of file would be PERFECT to use for FREE PPs and send them to Mikesal........1 hour until file self-destructs, like Mission Impossible!

Try this.....

https://kbpdfstudio.qoppa.com/set-ex...pdf-documents/

[wilderness]

Hey Tom,
Odd how we forget these things as time passes.
To defeat the date stamp, all is required is changing the OS date.

[Dave Schwartz]

Originally Posted by wilderness

Hey Tom,
Odd how we forget these things as time passes.
To defeat the date stamp, all is required is changing the OS date.

Do that in a modern day windows scenario and a ton of software will stop working.

[OverlayHunter]

Tom and Wilderness, thank you for the additional thoughts.

I've looked at each and every suggestion. At the moment, in terms of practicality and cost, G Suite (Dave's suggestion) seems to be the way for me to go. A couple of the other suggestions may be better solutions for others. I've posted 2 questions on the G Suite community forum but I will likely test it next week.

Thanks again to all of you for your time and good ideas.

[Magister Ludi]

link

[mikesal57]

Originally Posted by Tom

This type of file would be PERFECT to use for FREE PPs and send them to Mikesal........1 hour until file self-destructs, like Mission Impossible!

Try this.....

https://kbpdfstudio.qoppa.com/set-ex...pdf-documents/

You dont know how much damage I can do in that hour....

[Tom]

Originally Posted by Dave Schwartz

Do that in a modern day windows scenario and a ton of software will stop working.

Even when it is correct, not all works right.
TVG will not work on my laptop - it says date and time are incorrect and then shows me what it is set to and what it shold be set to - IDENTICAL!