In the process of implementing the Internet of Things, the object itself has identity information and identification equipment and encounters difficulties in communication security during the process of entering the network communication. Just like the Internet and wireless sensor networks, there are security issues in information transmission. Therefore, it is of great significance to study the mobile Internet of Things network security technology depression to protect the communication information in the mobile Internet of Things. This paper mainly studies the network security technology of intelligent information terminal based on mobile Internet of Things. This article will analyze and compare the mainstream encryption algorithms of the current mobile Internet and choose a safer and more secure HASH algorithm. We study the flow of key management, key generation, key distribution, verification key distribution, key update, key storage, key backup, and key validity time setting for mobile Internet of Things, using an existing identity cryptosystem. Based on encryption, the design technology of key management and authentication in this paper is improved. Compared with other methods, the storage consumption of this method on GWN is relatively medium. In the initial stage, the storage is 32 bytes, then in registration stage 1, it reaches 84 bytes, in registration stage 2, it is 82 bytes, and then, in the login authentication phase, the number of bytes rose and reached 356 bytes in authentication phase 3. Experimental results show that this protocol has certain advantages in ensuring safety performance.