Given h = sha256(k ∥ m), where k is a secret and "∥" means concatenation (no padding is involved in calculating h). describe a message x such that one can calculate sha256(k ∥ x) without knowing k. note that your described x should not the same as m, but could be a concatenated message

a macro is a tool that allows you to automate tasks and add functionality to your forms, reports, and controls. for example, if you add a command button to a form, you associate the button's onclick event to a macro, and the macro contains the commands that you want the button to perform each time it is clicked.

i do not get the question.