Abstract: Aiming at the problems of plaintext transmission, entity authentication and message authentication system in the current aviation very high frequency(VHF) technology in message transmission, a more applicable solution of message encryption and digital authentication is proposed based on the data link of aircraft communication addressing and reporting system(ACARS) and domestic SM algorithm. The scheme encrypts the body part of the message, and uses the public key cryptographic algorithm to sign the cipher text to obtain the corresponding signature value. The ciphertext and signature value will be combined in a specific format and then filled into the body part of the original message. Experiments show that using the symmetric encryption algorithm to process the message is superior to the asymmetric one in terms of payload size, encryption and decryption time, etc., and is more suitable for aviation VHF data links. The introduction of encryption algorithm and digital authentication into aviation VHF data link communication technology can ensure the confidentiality and integrity of the data link, improve the security of message transmission, and is of great significance to aviation information security.

Key words: very high frequency(VHF), aircraft communication addressing and reporting system(ACARS), SM4, digital signature, symmetric encryption algorithm, elliptic curve