Estimation of receivable distance for radiated disturbance containing information signal from information technology equipment

The present study was conducted to evaluate a leakage threat of information that can be reconstructed using radiated electromagnetic disturbance of information technology equipment. In this paper, the information leakage threat was estimated from a viewpoint of the receivable distance from the information technology equipment. The radiated electromagnetic disturbance of the information technology equipment is then based on the limits of the radiated disturbance for the information technology equipment of class B provided in CISPR 22. The estimation result reveals that the receivable distance exceeds hundreds of meters from the information technology equipment, taking account of the receivable capacity of a receiver with an antenna assumed in this paper. In addition, when the receiving frequency is higher, the receivable distance is shorter, in the defined frequency range with the constant limit value defined in CISPR 22. However, the receivable distance is stepped up at the receiving frequency of 230 [MHz], because at which the limit values of the radiated disturbance for the ITE of class B is stepped up.