A Chain Key Model Based on Message Hash Chain

To address the issue of key lifespan in key security, a chain key model based on a message hash chain is proposed. This model breaks away from the traditional scheme of generating random keys using random number generators, using plaintext features as a source of randomness, and generates the next key in conjunction with the current key, achieving key updates on a per-packet basis. The verification of the message hash chain node values ensures the consistency of the keys. The model utilizes messages and hash functions to enhance the randomness and secrecy of the keys. Security analysis shows that the complexity of cracking any key is O(2^n) . Experiments indicate that compared to the IPsec system, this model significantly reduces the lifespan of keys, and the Hamming distance, autocorrelation coefficient, and entropy value of the generated key hash chain conform to random characteristics. By introducing this model to generate the seed keys for the Salsa sequence cipher, the security and randomness of the Salsa sequence cipher are enhanced, increasing its complexity from the original O(2^n) to O(m2^2n), and when the transmitted message is 1400 bytes, the encryption efficiency is improved by more than 35% compared to the use of AES encryption in IPsec.