As MS4 inserted code consists of 3-6 lines of code per date field, the run time performance is negligible. Encapsulation MS4 creates an environment within which all dates are encrypted. The recommended decrement is 28 years, since this preserves both day of the week and leap year phasing. Within 'the environment' all programs and files process dates as if they were still in the 20th century, even though the real world date is in the 21st century. Dates from outside 'the environment' which are going in are encrypted.
Encapsulation has many advantages over other strategies.
It is extremely quick to implement. Our experiences with users of MS4 indicate that users can begin testing the date shifted system after about 5 days. The procedure is almost non-invasive. No changes are made to the layouts of files or the internal logic of programs. A small implant is inserted in those programs where dates are either passed in or out of 'the environment' in order to perform encapsulation.