RADIO COMMUNICATIONS SYSTEM, AND RADIO DEVICE USED FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a radio communication system which can suppress the eavesdropping of a secret key. SOLUTION: While the directivity of an array antenna 20 is switched to the directivity of n pieces, n pieces of electric waves are transmitted and received between radio devices 10 and 30. Further, the radio device 10 detects the n pieces of first electric wave intensity corresponding to the first n pieces of electric waves received from the radio device 30. By carrying out a predetermined operation to the first detected electric wave intensity of n pieces, a secret key Ks1 composed of a bit stream is created on the basis of the first permutated electric wave intensity of n pieces which are performed by the predetermined operation. Further, the radio device 30 detects the n pieces of second electric wave intensity corresponding to the second n pieces of electric waves received from the radio device 10. By carrying out a predetermined operation to the second detected electric wave intensity of n pieces, a secret key Ks2 composed of the same bit stream with that of the first secret key Ks1 is created on the basis of the second permutated electric wave intensity of n pieces which are performed by the predetermined operation. COPYRIGHT: (C)2008,JPO&INPIT