The Design And Implementation Of Secure Scanning Circuit For Encryption Chip

With the development of communication technology and Internet technology,information technology became the inevitable trend of social development and the network became an essential tool for people’s daily life.Both of them bring the information security issues.To solve this problem,encryption chip and other hardware-based encryption technology are applied to the communication device.However,the scan chain inserted into the chip became a backdoor,which can be attacked by hacker in side channel and cause the important data being stolen.Therefore,the modern communication technology in the encryption chip needs a kind of security scanning testing technology,which can both ensure the testability and information security of the chip.In this paper,for the requirements in security scan test of AES(Advanced Encryption Standard)encryption chip,a new technology called key isolation security scan chain is proposed.The function of the security scan chain is to separate the intermediate value register related to the key in the encryption chip from other registers and make the former a single chain.At the same time,some of the scan registers are replaced by the security scan registers.Secondly,the security scan chain is separated from the key generation circuit to add the key isolation control circuit,which can control the key to be loaded or not.The circuit consists of three parts: security scan chain circuit,key isolation circuit and key controller circuit.Among them,the key isolation circuit separates scan chain circuit from the key generation circuit,and the key controller circuit can make key isolation circuit loading key.The key isolation control circuit consists of the key isolation circuit and the key controller circuit.Under the function mode,the key is loaded into the encryption circuit for normal encryption.Under the test mode,it can be divided into two modes: no-key test model and key test model.Under the former model,the key which not loaded into the encryption circuit,be separated by the key isolation circuit.Under the latter model,the user enters the correct test password,and then the key is loaded into the encryption circuit so as to test the chip completely.The key isolation security scan chain technology based on AES encryption chip,using standard digital circuit design process.The probability of encryption chip being cracked is 1/(1.6*1039),in addition,the area increased by 0.58%.Prove the feasibility of this technology.