All users have a private and confidential file on their computer so that they do not want third parties to read it, so the best thing in these cases is to directly encrypt the content of that text file.
Mince is a very tiny, basic and simple utility that is responsible for encrypting your text files, and so if someone tries to access those files they will not be able to understand what it says, it will be all illegible when it is encrypted (it is as if it were encrypted).
To be able to decrypt it again (and thus be able to access it) you will only have to enter your access password in Mince.
You can free download Mince 32, 64 bit and safe install the latest trial or new full version for Windows 10 from the official site.