MULTOS (which stands for "Multiple Operating System") is an operating system that allows multiple application program s to be installed and to reside separately and securely on a smart card . Each program is isolated by the operating system so that no application can interfere with another one. Whereas earlier smart card systems did not allow new applications to be installed or old ones deleted, MULTOS makes this possible. Updates or patches can also be installed as needed. Each application is platform -independent due to the implementation of a virtual machine . Developers write applications for MULTOS smart cards using the MULTOS Executable Language (MEL).
Before MULTOS, application developers had to write a separate version of the application for each type of smart card and the consumer needed a separate smart card for each application. With MULTOS, several applications can reside on one smart card regardless of the microchip used.
Security for MULTOS smart cards is enabled by the MULTOS Certification Authority ( CA ), which issues cryptographic key s for each MULTOS smart card and all MULTOS applications. These keys prevent unauthorized applications from being loaded into a card or deleted without the issuer's permission.
The MAOSCO Consortium, a group of leading international organizations, openly licenses the MULTOS specification. MasterCard, Mondex, Europay, and Discover favor MULTOS.