I am not sure that 'security through obscurity' is always a bad thing. It is a rubric; and, as my culture hero Justice Holmes said, "We must think things and not words".
Immediately to the point here, I know how to intercept inputs to the z/OS FLIH, but I see no good reason to post code for doing so here and many good reasons not to do so. The best security is, as we all presumably know, provided by a transparent scheme the penetration of which req John Gilmore, Ashland, MA 01721 - USA