title: python 3 txt file digital signature and verification
body: <p>I am using python 3.
  I coded a program that creates some text files daily. 
  I want to sign these files and verify when necessary that these files haven not been changed and stayed original from signing. So, can I create a timestamp prove?
  <a href="https://stackoverflow.com/questions/50608010/how-to-verify-a-signed-file-in-python">How to verify a signed file in python</a> I found only that topic. How can I do that? What modules should I use and how?  </p>