| In the context of the Internet of Everything,WLAN relied on its fast access,high-speed transmission and other characteristics to play a pivotal role,but attackers could sniff the key information of key agreement to achieve password cracking and information theft.Therefore,improving the key agreement protocol had important research value.This article builded WiFi software and hardware platforms in the embedded way,and configured automated scripts to establish WiFi connections.Using the aircrack-ng suite of the Kali Linux system,the violence dictionary attack experiment was completed to verify the vulnerability of the random numbers through plaintext transmission in the WPA/WPA2 pre-shared key mechanism.The paper proposed the method of mixing the domestic symmetric algorithm SM4 and chaotic mapping Logistic,and the communication programs were optimized to improve the security of WLAN key negotiation protocol.The improvement work mainly included:(1)To avoid interception of the initial chaotic parameters during wireless transmission,the system parameter ? and the initial value x0 were pre-stored at both ends of the authentication before the key negotiation.The Logistic chaotic system iteratively generated a pseudo-random real-valued sequence,and a 128-bit SM4 initial key was obtained after threshold quantization.(2)The SM4 algorithm read the chaotic initial key and generated 32 round keys through key expansion.The random numbers ANonce and SNonce generated by both authenticated parties were encrypted.The key agreement data packet no longer contained the random number plaintext,and the correct integrity check value could not be obtained through cyclic calculation and comparison,and the correct WiFi password could not be derived.Testing and analyzing indicators such as randomness,jitter,sensitivity,bandwidth,the results showed that the improved system satisfied the communication performance while effectively improving the security of key agreement. |
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