A cyclic redundancy check (CRC) performs the same function as a parity bit for large streams of data with less overhead than parity bit technology. CRCs are calculated by the sender using a mathematical function applied to the data to be transmitted to create a fixed size output. The CRC is appended to the transmitted data. The receiver calculates the CRC from the data stream and matches it against the CRC provided by the sender. If the two match, the data has not changed accidentally.