To solve the problem of that conventionally data communication method for a wireless terminal and a wireless base station in a wireless network system that has the risk of data being intercepted and decoded, because a common key is exchanged by the public key and the private key of the wireless terminal, and the wireless base station and the data are encrypted by using the common key.

In the data communication method between the wireless terminal and the wireless base station, the common key, an imbedded position of a scramble cod and its code length are exchanged between the wireless terminal and the wireless base station by using the public key and the private key, a scramble code with a length denoted by a code length is generated in units of data packets, the data are scrambled by the generated scramble code, the scramble data in which the scramble code is placed at the imbed position are added to data to be scrambled and the data are further encrypted by the common key, and the data communication is conducted.