Cyclic Redundancy Check, an advanced checksum technique used to recognize errors in digital data. It uses a check value calculated for a data stream by feeding it through a shifter with feedback terms ‘EXORed’ back in. It performs the same function as a checksum but is considerably harder to fool.

A CRC can detect errors but not repair them, unlike an ECC. A CRC is attached to almost any burst of data which might possibly be corrupted. On disks, any error detected by a CRC is corrected by an ECC. ITU-R BT.601 and 709 data is subjected to CRCs. If an error is found the data is concealed by repeating appropriate adjacent data. Ethernet packets also use CRCs.

See also: Asynchronous, Checksum, ECC, EXOR