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hazenweberFlag for United States of America

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Auto-Lock a file based on date

I have a client that sends files to organizations with time sensitive data.  She doesn't want folks to be able to open the file after a certain date that she specifies.  These files are simple Excel files, but could be PDF, DOC, or even ZIP files.  She wants a program she can run, select a file she will send, and specify in the application that the selected file should lock itself so it can't be opened in 10 days.  Then she wants to send that file to these organizations.
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Dave Howe
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Till now it is not possible to apply any individual file (by using generic software).
But you can use/create any container/host (customized) program that will contain the file (encrypted) and make the file viewable for certain time, but never write file to the disk and prohibit any copy/snap/print. The problem is, why other organization blindly trust an executable file (which they can not control)?
sadidev: the problem there is ensuring that the clock is accurate - otherwise, you just set the clock back into the "valid" period and the file opens...
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not even an internet clock can really be trusted - you need to run your own server, at which point you are probably better off just doing what invisible inc did - host the content on the server and allow it to be viewable though an applet.
Actually nothing can be 100% secure. Trusted server can be spoofed. Of course there are always better way to secure something. We can make something, that might be harder to break. Anyway thank you (DaveHowe) for pointing to it more specifically.
trusted server can't be spoofed, provided you use PKI - but as I say, if you have to run a server anyway, host the content locally to the server, access it though a java applet or flash applet, and all the client has to do is pass a couple of parameters (document id and auth string) to read the document up to the point the server is told to no longer accept that auth string.

anything else is asking for the local applet to be hacked to not bother checking the date.