What is the principle of Bluetooth technology?

How Bluetooth technology works: Bluetooth devices use radio waves (instead of wires or cables) to connect mobile phones and computers. When Bluetooth devices want to communicate with each other, they need to be paired. After successfully creating the network environment, one device is the master device and all other devices are the slaves. When Bluetooth devices join and leave short-range radio sensing, piconets are established dynamically and automatically.

Bluetooth is used for wireless connection between different devices, such as connecting computers and peripheral devices, such as printers and keyboards, or allowing personal digital assistants (PDA) to communicate with other PDA or computers nearby.

There are many mobile phones with Bluetooth technology on the market, which can be connected to computers, PDA and even hands-free headphones.

In fact, according to the established standards, Bluetooth can support more powerful long-distance communication and form a wireless local area network. Each Bluetooth device can keep 7 connections at the same time. Each device can be configured to constantly announce its presence to nearby devices in order to establish a connection. In addition, the connection between two devices can also be password protected to prevent it from being received by other devices.

Extended data

The problems existing in Bluetooth mainly include the following:

(1) Power consumption of Bluetooth. Bluetooth transmits data infrequently and consumes less energy in the process of data transmission. However, in order to respond to the connection request in time, polling access in the waiting process is very energy-consuming. ?

(2) The Bluetooth connection process is complicated. Bluetooth connection involves many times of information transmission and verification, and on the surface, it doesn't seem to make users feel that the connection procedure is complicated. However, the repeated data encryption and decryption process and the authentication process required for each connection are a great waste of computing resources of the device.

(3) The security of Bluetooth. The first pairing of Bluetooth requires the user to pass the PIN code verification. PIN codes generally consist of only numbers, with few digits, usually 4-6 digits.

After the PIN code is generated, the device will automatically encrypt the PIN code using the E2 or E3 encryption algorithm that comes with Bluetooth, and then transmit it for identity authentication. In this process, hackers are likely to intercept data packets, pretend to be target Bluetooth devices to connect or use "violent attacks" to crack the PIN code.