The program possible logical device and its security manner which security of design specification are strengthened

摘要

(57) Abstract With this invention, it can use the security bit of two or more at the time of the block of the PLD tip/chip. When the security bit everything being a state where it is erased, to remain with internal constitution and other information conservation, internal constitution and other information conservation one or by programming all security bits. The security bit is laid out approaching to the field where information of configuration and the data which the other users define have entered, physically. With that, when it becomes difficult, to find the security bit in addition everything erases the security bit of EPROM based PLD, approaching, also the bit which the user which exists defines is erased large number. As a result, secrecy it becomes difficult depending upon the reverse engineering to pull out useful information from the device conservation. The security bit it makes the security bit difficult, to be discovered by the fact that it lays out in the pseudo random number position while each block of the tip/chip which differs, it is possible to make the reverse engineering difficult.