Java Card

Java Card refers to a technology that allows small Java-based applications (applets) to be run securely on smart cards and similar devices. It is widely used in SIM cards (used in GSM mobile phones) and ATM cards.

The first Java Card technology - based smart cards were introduced in 1997 by several companies including former Schlumberger's card division (now Axalto) and Gemplus. Java Card products are based on the Java Card Platform specifications developed by Sun Microsystems.

The main features of this technology are portability and security.

程式移攜性

The Java Card VM, responsible for interpreting the Java applet instructions, is a subset of the Java VM, and thus requires less space in the host media than the Java VM. Additionally, Java Card applets are also smaller, an aspect which further contributes to their portability.

A trade-off for this feature, however, is that not all Java features are supported, and the size and memory resources are limited. Although there are methods for overcoming the size limitation of an application, such as dividing the application's code into packages, the size of each package still may not exceed 64 KB.

防護安全性

Java Card technology was originally developed for the purpose of securing sensitive information stored on smart cards.

防護安全性取決於幾種角度：

• Data encapsulation. Data is stored within the application, and Java Card applications are executed in an isolated environment (the Java Card VM), separate from the underlying operating system and hardware. Different applications are additionally separated from each other by an applet firewall.
• Cryptography. The most commonly used encryption algorithms (including elliptic curve cryptography) are supported.

The financial sector, as well as the communications sector, currently rely on this technology for securing information in smart card media.

相關參見

• Java Card OpenPlatform（簡稱：JCOP），爪哇卡開放平台是一個以Java Card為基礎的作業系統，且因使用Java Card技術而具有安全防護性。-（英文）

外部連結

• Java Card平台規格（昇陽電腦）-（英文）

• 智慧卡的基礎知識-（英文）