[Cryptography] A two key file/program

[Matt Palmer]

On Thu, May 16, 2019 at 07:00:34PM -0700, Allen Schaaf wrote:
> I'm looking for a program or file system to run on Windows 7/8.1/10 to keep
> data protected that requires two separate keys used at the same time to open
> the file. It needs to be like the missile launching system that was created
> using two physical keys at the same time to prevent one crazy person from
> starting a war.

[...]

> I recall that there is a system like this but I'm unable to find it. Given
> that it is a very small credit union and that it functions in a lower income
> market it would be best if it was free or low cost.

The *concept* you're looking for, I suspect, is Shamir Secret Sharing.  I
don't know of any implementations specifically for Windows (not really my
thing), but I'm sure with that keyword and a little bit of DDG-fu you'd dig
something up fairly quickly.

- Matt