Check sum is used for –

A checksum is a value calculated from a block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage.

• The Process: The sender calculates a numerical value based on the bits in the data packet and appends it to the packet. The receiver performs the same calculation on the received data.

• The Verification: If the receiver’s calculated value matches the sender’s checksum, the data is assumed to be intact. If they don't match, the receiver knows the data has been corrupted.