Java Card

Java Card is a version of the Java programming language, which allows Java Card applet, a reduced standard Java following Java Applets to run on smart cards.

Java Card applets are executed only when a smart card is connected to an external power supply and the Java VM of the card has been instructed to select a particular applet. The security mechanisms of the Java allow a Java smart card may contain multiple Applets that do not influence each other, as far as the capacity of the card is not exceeded. Java Card applets can be installed separately on a Java smart card and, as Java programs, the hardware of the smart card regardless. Java Card applets communicate exclusively via APDUs ( Application Protocol Data Units ) with a connected card reader; a possible protocol for this data channel is Java Card Remote Method Invocation, a protocol for calling object methods between Java VMs.

Java Card applets are primarily for the safe storage and use of cryptographic keys. The keys may be generated for this purpose on the chip card and a reading of the private key of the card is prevented as far as possible.