The SYSV checksum algorithm is a commonly used, legacy checksum algorithm. It has been implemented in UNIX System V and is also available through the GNU sum command line utility.
Contents
Newer checksum algorithms
The manual page of the GNU sum utility program (that implements the BSD checksum algorithm) states: "sum is provided for compatibility; the cksum program is preferable in new applications."
Description of the algorithm
The main part of this algorithm is simply adding up all bytes in a 32-bit sum. As a result, this algorithm has the characteristics (disadvantages and advantages) of a simple sum:
As a result, many common changes to text data are not detected by this method.
The last two lines of the algorithm reduce the total sum to a 16-bit number.
References
SYSV checksum Wikipedia(Text) CC BY-SA