public abstract class Checksum
Interface to compute a data checksum used by checked input/output streams. A data checksum can be updated by one byte
or with a byte array. After each update the value of the current checksum can be returned by calling
getValue. The complete checksum object can also be reset so it can be used again with new data.
Changes for TotalCross:
To improve performance, Checksum is an abstract class rather than an interface.