Issue
97, August 1998
Designing
for Smart Cards
- Part 2: Practical Implementation
SOFTWARE
DEVELOPMENT
Once
the nonvolatile memory size is agreed on and a vendor
chosen, you can begin software development. Over the
past 10–15 years, OSs in smart cards have evolved
from simple, single-application cards to current GSM
SIM cards with multiple applications (see Figure 1).
|
Figure
1—The memory needs of multiapplication
cards are much greater than for single-application
cards, and so are the needs to isolate each application
from the others.
|
The
goal of the OS is to ensure a simple application that
can be used anywhere. The software must be essentially
error free because it is commonly implemented in ROM
and, thus, is expensive and timely to repair.
The
OS needs to provide communications with card readers,
execute only predefined ISO commands (as pertinent to
the card’s application), manage data and authorization,
and ensure execution of encryption algorithms.
