Forget about phrases like “guaranteed”, “absolute integrity”, “assured”. There is really only one thing that you need to know about all those systems that you are currently running, mission-critical or not – absolutely all applications are insecure. The certainty of this statement was shown by fundamental research in computability from the legendary code-breaker Alan Turing.

One of the essential findings of his ground-breaking work was that it was not possible to automatically demonstrate in advance how any particular computer program would respond to all particular inputs.