Rings of the Master #1: Lords of the Middle Dark by Jack L. Chalker

Long ago, the machines had rebelled, wiping out most of humanity and exiling the survivors in widely scattered reservations. Master System ruled unchallenged, the key to breaking its power — five microchips disguised as gold rings, carefully hidden away. But then an Amerindian called Hawks stumbled across information about the five rings, and suddenly Master System developed an interest in seeing Hawks dead . . .