Checksum
From uCtrl.net
Information
A checksum is a simple way to protect the integrity of data by generating a short code based on a longer sequence of data. If the data has been changed the checksum will probably not match with the new file. This is often used to control that files transfered over the internet, have not been damaged. I also use it for Serial I/O system communication, all modules end their commands with a checksum.
