CRC (cyclic redundancy check) is a better error checking method when compared to the parity bits. CRC uses some complex mathematical calculations to check for errors during data transmission. This method is said to identify up to 99.99% of errors. The CRC is ordinarily applied to digital data or networks, and storage systems such as CDs, DVDs or hard disk drive.
Some extra information (checksum) is attached to the message that is sent and this extra information helps to determine if the message was received as sent, that is, if the message was correct.
How Does CRC Actually Work?
CRC views a message as a polynomial, and a checksum is added to the end of the packet and the polynomial represented by the checksum packet can be divided by a given variable, when the message or packet gets to the receiving address, a division is performed on the polynomial, if the result generates a reminder, then there is an error in the message a NAK (negative acknowledgement) is then sent back to the sender to prompt a resending of the message. If the message is received correctly, an ACK (acknowledgment) is sent to acknowledge the receipt of the message.