Security of Software-Defined Radio
The concept of Software-Defined Radio (SDR) was first proposed in the United States in 1992, with the goal of establishing a new architecture for wireless communication systems. Its fundamental idea is to use hardware as a platform for wireless communication and implement as many wireless and personal communication functions as possible through software.
Similar to the development trajectory of many other technologies, SDR was initially only applied in military radio systems. However, times have changed, and the mass market has now begun to embrace SDR. Currently, SDR is gradually being commercialized and has found applications in both base stations and terminal devices. In wireless communication technology, the development of new systems and products is increasingly trending towards multifunctionality, compatibility, and intelligence. As a representative of this trend, SDR technology is poised to demonstrate even greater value in the field of wireless communications. However, along with the rapid development of SDR, certain issues have also emerged.
1. Current State of Radio Communication
The principle of radio technology lies in the fact that changes in the strength of an electric current in a conductor generate radio waves. By utilizing this phenomenon, information can be loaded onto radio waves through modulation. When these waves propagate through space and reach the receiving end, the changes in the electromagnetic field induced by the waves generate an electric current in the conductor. The information is then extracted from these current variations through demodulation, achieving the purpose of information transmission.
Currently, radio communication technology is undergoing a transformation. Numerous technological innovations have emerged in the field, leading to further advancements in communication methods. The application of digital communication technology has made signals in wireless communication more stable, reduced external interference, and further increased the transmission capacity of wireless communication. New encoding methods and encryption algorithms have enhanced information confidentiality. The emergence of core radio communication technologies, such as Wi-Fi, 3G, and 4G, has enabled faster and broader radio communication, expanding into more and larger domains.
2. Hidden Dangers in Radio Use (Using Remote Control Technology as an Example)
Radio technology is now widely used in remote control devices, such as garage door openers, car anti-theft devices, and remote-controlled toys. The greatest advantage of radio frequency (RF) remote controllers is their range: they can transmit signals up to 30 meters from the receiver, and wireless signals can pass through walls. The problem with RF remote controllers is the multitude of wireless signals constantly propagating through the air. Mobile phones, walkie-talkies, wireless internet devices, and cordless phones all transmit wireless signals at different frequencies. RF remote controllers address interference by transmitting specific radio frequencies and embedding data address codes into the radio signal. This way, the wireless receiver on the controlled device knows when to respond to the signal and when to ignore it. However, this leads to security issues in radio use. Since radio signals are constantly transmitted through the air, they can be easily captured, resulting in the leakage of radio information. While many devices effectively prevent information loss through measures such as protocol encryption, for some devices, relying solely on protocol encryption is insufficient. Security vulnerabilities can interfere with device operation or even damage the device.
Nowadays, problems caused by the use of radio technology are everywhere. More and more car manufacturers are equipping their models with wireless key systems and remote car locks, allowing car owners to lock and unlock their doors via remote keys. While this functionality provides convenience, it also poses significant security risks. A product known as a "car signal transceiver" has been circulating online. This device is a signal transmitter capable of mimicking the signals of a car owner's remote key. Using such a device, thieves can easily control the car's remote system and steal items from inside the vehicle. Some thieves even copy the remote signals of stolen cars to rob other vehicles or directly steal the cars themselves.
