Multi ApplicationOperating System (MULTOS) is an open platform
for smart card applications. The applications for MULTOS are loaded onto the smart cards and managed there. New applications can be created in the programming language C or Java
. The protocol stack MULTOS consists of the BasicProcessor Functions (BPF), the overlying Multi-Application OS (MAOS) and the Application Abstract Machine (AAM) on which the different applications are located. The Basic Processor Functions (BPF) comprise the hardware driver, the I/O functions, the crypto controller and the securitylogic.