A circuit generally comprising a plurality of master modules and a
supervisor module is disclosed. The supervisor module may be configured
to (i) detect a target address and a particular master module of the
master modules initiating a transaction on a bus, (ii) identify a
predetermined authorization in response to the particular master module,
the target address and a current security mode of at least three security
modes and (iii) subvert the transaction in response to the predetermined
authorization restricting the transaction.