Lock Isolation Security Structures And Test Methods For Reconfigurable Scanning Networks

A large number of embedded modules are integrated on the chip.In order to test and access the embedded instruments flexibly,the IEEE P1687 standard is proposed.The standard is connected with the chip through the IEEE 1149.1 standard test access port.The SIB in the network can access the embedded instruments flexibly and conveniently by configuring the active scanning path.Although the reconfigurable scanning network has the advantage of flexible access to instruments,there are three kinds of security attacks: unauthorized access,data sniffing and data tampering.In addition,if there is a hardware failure in the network configurable module,the configuration and test of the instrument will be affected.Aiming at the security problems in reconfigurable scanning network and the testing problems of configurable modules in network structure,this dissertation proposes effective solutions.The major works is as follows:1.The lock isolation security structure and the instrument grouping algorithm for reconfigurable scanning network are proposed.In order to solve the data sniffing and data tampering attacks between instruments,the instruments with security threats are divided into different groups,and the separate access of each group is controlled by isolation signal.For instruments with high security in the network,lock segment insertion bits associated with multiple key bits are used to increase the difficulty of unauthorized access.Only when multiple key bits are moved into a specific value(0,1sequence),can lock segment insertion bits be updated and configured.In addition,an instrument grouping algorithm is proposed for instrument grouping test,which can get less instrument grouping number according to the security relationship between instruments,and avoid the problem of hardware overhead caused by too many groups.The experimental results on ITC 02 benchmark show that the lock isolation security architecture can deal with three kinds of security attacks in reconfigurable scanning network.Compared with other methods,the cost of area,power consumption and wiring are reduced by 3.81%,9.02% and 4.55% respectively.At the same time,the instrument grouping algorithm can also get a better number of instrument packets.2.A minimum configuration test algorithm is proposed to test the configurable modules in the lock isolation security architecture.The algorithm is based on the network configuration transformation graph.Starting from the initial configuration,the algorithm obtains the adjacent configuration set and the faults that can be tested by each adjacent configuration according to the current configuration.The fault set corresponding to each adjacent configuration is the fault set of the previous configuration minus the fault set that can be tested by this configuration.The algorithm recursively executes all the adjacent configurations until the fault set of a configuration is empty.From the initial configuration to the configuration,the reconfigurable scan network can be fully tested.Experimental results show that compared with other methods,the proposed algorithm can be applied to lock isolation security structure and ordinary IEEE P1687 network structure at the same time,and the average test time is reduced by 2.6%.