Programming the SIM

Writing a program to be executed on a SIM is, as already discussed, very similar to programming a 20-year-old computer. Until very recently, that meant assembler code, lots of hard work, and no portability between cards. Recently, however, things have improved a great deal, with standardized operating systems for smart cards (and SIMs). There are now several competitive systems looking to simplify things.

JavaCard

Ø       Based on the Java VM model

Ø       Allows programming in subset of Java language

Ø       Owned by Sun Microsystems

Ø       Already integrated into GSM SIMs

Windows for Smart Cards (WinCard)

Ø       Based on the Windows operating system!

Ø       Promoted by Microsoft

Ø       Only just available, but will be popular due to MS backing

Ø       Allows programming in a Visual Basic like manner

Multos

Ø       Operating system used by Mondex

Ø       Owned by MasterCard

Ø       Unlikely to see Visa using it!

Ø       Deployed in several applications around the world

Ø       Integrated, recently, into GSM SIM. Allows access to:

Ø       Strong encryption

Ø       Stored cash system