checksum:    the calculated value of a cyclic redundancy check (CRC) that is dependent upon the contents of the message. The message is often a packet. The calculated value is sent along with the message or packet when it is transmitted. The receiving system calculates a new checksum based upon the received data and compares this value with the one sent with the message or packet. If the two values are the same, the receiver has a high degree of confidence that the data was received correctly. If the checksum is transmitted by an independent path, confidence becomes trust (a secure checksum). c.f. hash, HMAC

See also: TBD