| 摘要 |
<p>With a view to preventing access to data stored in a computer installation by remote sensing of stray electromagnetic radiation emitted by the installation, a transmitter is provided within a housing 8 for transmitting electromagnetic radiation over a frequency range which includes at least the main frequencies at which stray radiation is emitted by the installation. An antenna 9 is coupled to the transmitter and attached to the installation. In this manner the stray radiation emitted by the installation is substantially masked by the radiation transmitted by the device. Such a device is capable of protecting substantially any type of computer installation, and of preventing an unauthorised person from reading displayed data or other information within the computer by means of a remote receiver, visual display unit or data reader.</p> |
