| In recent years,the requirements for data security have increased,and the security of cryptosystems is particularly important.Chaotic systems are used in cryptography because of their pseudorandomness and sensitivity to initial conditions.The security of chaotic cryptosystems is generally evaluated by classical statistical tests,such as the SP 800-22 test,the avalanche test,etc.,and the attack on the chaotic cryptosystem is mainly based on mathematical methods.However,when the cryptosystem is running,it will leak side channel information such as power consumption,electromagnetics,and sounds,which are often related to the data processed by the cryptosystem.The side channel attack utilizes the correlation between the intermediate data processed by the cryptosystem and the side channel information,which can greatly reduce the search space of the key.Many cryptographic algorithms that are proven to be safe in mathematics,such as the Advanced Encryption Standard(AES),Data Encryption Standard(DES)algorithms,are subjected to a serious threat to the side channel attack.But few works have evaluated the security of chaotic systems from the hardware perspective.So,in this paper two cryptographic algorithms are attacked using the power analysis attack respectively,one of them is based on the substitution-permutation(SP)network,and the other is based on the Feistel structure.Aiming at the drawback of the cryptosystem,the protection methods are given.The main contents of the research are given as follow.1.Verify the hardware security of a chaotic cryptosystem which is based on the SP structure using the side channel attack.A chaotic block cipher based on SP network is designed,and its statistical security is tested using conventional statistical tests such as SP 800-22 test,avalanche test,etc.,then the algorithm is implemented on an Atmel XMEGA 128D4 microcontroller unit.Finally,the power analysis attack is carried out on the cryptosystem.The experimental results show that although the cryptosystem has passed the statistical tests,there is still the possibility of being attacked using the side channel attack.2.Verify the hardware security of the chaotic cryptosystem which is based on the Feistel structure using the side channel attack.The Feistel structure is a common structure of block ciphers,and the cryptosystems based on the Feistel structure consume less resource.In this chapter,the power analysis attack is carried on a chaotic block cryptosystem which is based on the Feistel structure.The efficiencies at different attack points are compared in detail.The experimental results show that the cryptosystem can be broken within 50 plaintexts.3.The protection methods including the masking and hiding are applied on the cryptosystem which is based on the SP structure.The cryptosystem can be upgraded within a low cost,for the protection methods are designed at the algorithm level.A total of 350 sets of plaintexts are used for the power analysis attack.The correct key and the wrong keys cannot be separated,which proves the feasibility of the protection method. |
