It has been implemented in UNIX System V and is also available through the sum command line utility.
This algorithm is useless on a security perspective, and is weaker than the CRC-32 cksum for error detection.
[1][2] 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 of a simple sum:[2] As a result, many common changes to text data are not detected by this method.
The FreeBSD pseudocode for this algorithm is: The last part folds the value into 16 bits.