<i>[...] if a voltage is applied to a seemingly unused pin, another pin suddenly begins broadcasting the internal state of the chip after every stage of the algorithm.</i><p>That sounds like a JTAG ( <a href="http://en.wikipedia.org/wiki/Joint_Test_Action_Group" rel="nofollow">http://en.wikipedia.org/wiki/Joint_Test_Action_Group</a> ) scan for test purposes. Basic idea is that registers on logic block boundaries are turned into a shift register that pumps out the internal state.