The invention discloses a
chip scanning test
encryption circuit based on a Rossler
chaotic system and a test method, and relates to the field of
integrated circuit testability design safety. In order to make up for potential attackable vulnerabilities in a traditional
password verification or
stream encryption test scheme, a pseudo-
random sequence generated by a
chaotic system is introduced during
encryption and decryption of
test data, and high initial value sensitivity and nonlinearity of the
chaotic system are utilized to effectively
resist attacks aiming at classical
stream passwords and improve the security of a scanning test. The scan test encryption circuit comprises a Rossler chaotic sequence generation module, a bit recombination module, an internal or
boundary scan chain, a JTAG test access controller, a parallel-serial
data conversion module, a perturbation unit and the like. The scanning encryption test method comprises the following steps: simulating on a computer to obtain a chaos pseudo-
random sequence; performing XOR on the pseudo-
random sequence and the original
test data to obtain an encrypted
test vector and a response thereof; the test
machine injects the encrypted
test vector into the to-be-tested
chip, and meanwhile, the test
machine obtains the response of the previous encrypted
test vector; and comparing the read encrypted
test response with the encrypted response stored in the test
machine. The scanning test encryption circuit and the test method are compatible with an IEEE-1149 protocol interface and can continue to use existing test machine equipment.