Learning cyclic redundancy CRC check

Definition （ From Baidu Encyclopedia ）

Cyclic redundancy check （Cyclic Redundancy Check, CRC） It is a kind of channel coding technology that generates short fixed digit check code according to data such as network packets or computer files , It is mainly used to detect or verify the possible errors after data transmission or saving . It uses the principle of division and remainder to detect errors

brief introduction

In the process of data transmission , No matter how perfect the design of the transmission system , There will always be mistakes , This kind of error may cause one or more frames transmitted on the link to be destroyed ( Bit error ,0 Turn into 1, perhaps 1 Turn into 0), So the receiver receives the wrong data . In order to improve the accuracy of data received by the receiver as much as possible , Before the receiver receives the data, error detection of the data is needed , When and only when the detection result is correct, the receiver can receive the data . There are many ways of testing , Parity is common 、 Internet check and cyclic redundancy check . Cyclic redundancy check is a calculation method used to check the accuracy of digital transmission on communication link （ Establishing the agreed relationship between data bits and check bits through some mathematical operation [1] ）. The information contained in a formula is calculated by the sender , And set this value Attached to the transmitted data , The receiving computer updates the same data Same calculation , Should get the same result . If these two CRC Inconsistent results , There is an error in the transmission , The receiving computer may ask the sender computer to resend the data .

working principle

give an example