Cyclic redundant check. Used in data transfer to check if the data has been corrupted. It is 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, which is attached to almost any burst of data that might possibly be corrupted. They are used on disks, ITU-R 601 data, Ethernet packets, etc.