The invention relates to the technical field of
data security, in particular to a chain
key exchange method, a
client, a
server and a
system. The method comprises the following steps: enabling a
client to generate a first public key and a first private key; sending the first public key to a
server, and receiving a second public key sent by the
server; generating an initial vector, and encrypting the initial vector by using a second public key to obtain a
client ciphertext; randomly
cutting the client
ciphertext into N parts, and carrying out distribution and exchange with a server to obtain server sub-
ciphertext; and combining the server sub-ciphertext into a server ciphertext, and decrypting the server ciphertext by using the first private key to obtain a
session key. On the basis of an original chain
key exchange protocol, corresponding improvement is made for possible man-in-the-middle attacks, traditional halving transmission is abandoned, an N-time chain
key exchange algorithm is adopted, the
encryption strength of data is greatly improved, attackers cannot crack the data within the
effective time of information. And the possibility that the secret-related information is cracked is reduced, and the
data security is ensured.