Checksum

From Unofficial BOINC Wiki

[edit] General

A simple error-detection scheme in which each transmitted message, or portion of a message, is accompanied by a numerical value. This numerical value is calculated by adding each data byte to the sum of all of the data bytes to this point, and discarding any overflow. his give a numerical value that reflects the bit content of the message or fragment. The receiving computer performs the same operations on the message or message fragment and then checks the checksum value sent by the originating computer to make sure the numerical value is the same. If the values are not the same, then the receiving computer can assume that the message has been garbled in transmission.

The weakness within this method of message validation is that multiple bit failures within the data stream can result in a "valid" checksum value even when the data is in fact corrupt. A more rigorous method is used in the operation of the BOINC Client Software is based on the MD5 algorithm.