Computer Science for IGCSE & O level - Data Transmission (Section 1 - No. 2)
Which technique does a checksum employ to detect errors in data transmission?
Adding extra bits to the beginning of the data.
Calculating a numerical value and comparing it at the receiver.
Using a public key to encrypt the data.
Re-sending the data multiple times.
Explication
A checksum calculates a value from the data that is then compared at the receiving end.