Review Case 5: Case 5-Reliability of Smart Cards. Following your review, identify the following and submit your answers in a Word document:
• Summarize the case
• Summarize the problem
• Describe the solution
• Discuss your thoughts on how well the solution addressed the problem and if you might have looked at the problem from another angle.
12.5 CASE 5: RELIABILITY OF SMART CARDS*
12.5.1 Introduction
During the 1990s when smart cards were first introduced, one of the major challenges was to demonstrate its reliability to its early adopters. One of the largest organizations in an island state was keen to adopt smart cards as its employees’ ID cards (Figure 12.10). The organization has about 300 000 employees and operates from a few hundred sites that require security access. With smart card serving as ID for every employee, vital employees’ data and passwords can be stored in the smart card. Smart card readers will then be installed at the entrances of various facilities and secured work-station so as to control, monitor, and record access centrally and remotely through computer network. It is thus important that smart cards and the readers must be highly reliable to ensure smooth work flow without compromising the desired level of safety and security. Physically, the size and make of a smart card are similar to those of a credit-card except that a memory chip with 24 memory cells is embedded in it. In fact, today, almost all credit cards are smart cards. The early generation of smart cards is slightly thicker than a typical credit card so as to ensure that the presence of the memory chip will not compromise its structural integrity and durability. With the structural durability out of sight, the key concern was the reliability in writing and reading data from the memory chip. Based on previous similar applications of memory chip designs, the smart card sup-plier claimed that the smart card can last for at least five years without the need for replacement. Before the adoption of smart card as the employee ID, the organization requested the smart card supplier to provide a third party assessment of the reliability of the smart card.
12.5.2 Statement of the Problem
The first task is to determine the “real” design life of the smart cards as it might prove unworthy to adopt five years as the expected design life. For example, in the event that the failure time distribution is exponential with MTTF = 5 years, 63.2% of the 300 000 cards would have failed by the end of 5 years. The disruptions to work flow and the associated logistics support to rectify these failures will be extensive. The key consideration is thus to ensure that it will not be seen as a major problem in adopting the technology. Once the design life is determined, the primary objective is to design a test plan to demonstrate that smart card operations meet the reliability target. Another issue is to relate the number of transactions to calendar time. It is decided to adopt the 80 : 20 principle by assuming that 80% of the users are “light” users with an average of 10 daily transactions while 20% are “heavy” users with an average of 50. It is also assumed that there are 300 working days/year.
