According to the foregoing descriptions of FIG. 6 and FIG. 7, it can be appreciated that only the Bluetooth host device 110 and the first member device 120 are required to respectively generate the corresponding first cypher key Key-1 and second cypher key Key-2 in this embodiment. Other member devices (e.g., the second member device 130 and the third member device 140) would directly use the second cypher key Key-2 generated by the first member device 120 to conduct subsequent Bluetooth data transmissions with the Bluetooth host device 110, without generating related cypher keys by themselves. Accordingly, by adopting the method of FIG. 6 or FIG. 7, it can significantly reduce the time and computing loading of other member devices of the Bluetooth device set 102 (e.g., the second member device 130 and the third member device 140) required for negotiating the key parameters with the Bluetooth host device 110, and also save their time and computing load required for generating the cypher keys.
