A checksum or hash sum is a small-size datum from a block of digital data for the purpose of detecting errors which may have been introduced during its transmission or storage. It is usually applied to an installation file after it is received from the download server. By themselves checksums are often used to verify data integrity, but should not be relied upon to also verify data authenticity.
英英词典
check sum n.
a digit representing the sum of the digits in an instance of digital data; used to check whether errors have occurred in transmission or storage