JavaCard Applet Template

An easy-to-use JavaCard project template including everything needed to quickly get started with developing a JavaCard applet.

Features

• Applet code template;
• Applet unit tests template;
• Build and test the applet with one command;
• All dependencies downloaded and included automatically;

Set-up

All paths are given relative to the repository root.

1. Install JDK, Ant, and Maven:
   1. You could use, for example, SDKMAN to manage your JVM-related SDKs;
   2. Supported JDK versions are 1.8, 11, and 17 for JavaCard 3.1.0; 1.8 and 11 for earlier versions;
2. Fetch JavaCard SDKs: git submodule update --init;
3. Set required JavaCard SDK version (the options are the sub-folders of sdk/javacard_sdks without the trailing _kit):
   1. sdk.version property in src/build.xml;
   2. sdk.version property in src/pom.xml;
4. Fetch other dependencies: cd src, ant fetch;
5. Build the applet: ant build;
6. The build outputs are in src/target:
   1. Applet compiled as a library for testing: <applet_name>.jar;
   2. Packaged applet for uploading to a card: <applet_name>.cap;
7. Test the applet: cd test, mvn test;
8. Upload the packaged applet to your smartcard:
   1. Recommended tool: GlobalPlatformPro.

Dependencies

• JavaCard SDKs - downloaded automatically as a git submodule;
• Ant-JavaCard - JavaCard build tool - downloaded automatically by Ant;
• JCardSim - JavaCard simulator used for testing - downloaded automatically by Ant;

Project structure

.  
├── sdk/ (external dependencies)
│   ├── javacard_sdks/ (JavaCard SDKs) 
│   └── ...  
├── src/ (applet module)
│   ├── src/ (source code)
│   ├── target/ (build outputs)
│   │   ├── template-applet.jar (applet as a library for testing)
│   │   ├── template-applet.cap (packaged applet for uploading to a card)
│   │   └── ...
│   ├── build.xml (Ant build script)
│   └── pom.xml (Maven configuration - needed for some IDEs to locate dependencies)
├── test/ (applet tests module)
│   ├── src/ (code)
│   │   ├── test/ (tests)
│   │   └── main/ (helper classes)
│   └── pom.xml (Maven configuration)
└── ...  

Configuration guide

The two modules the project consists of are tightly interconnected, so changes in one need to be reflected in another for everything to work. This section describes (hopefully) all the steps you need to take to change some parameters.

• Change the applet class name:
  • Rename the class (initially com.vadimtch.applet_template.src.MyApplet) and the file it is in;
  • Update the applet.class property in src/build.xml;
  • Update the applet class name in appletClass in com.vadimtch.applet_template.test.SimulatorWrapper;
• Change the Java package name:
  • Change the package name in the source files;
  • Rename the package directories in:
    • src/src/main/java;
    • test/src/main/java;
    • test/src/test/java;
  • Change the applet.class property in src/build.xml;
  • Change the groupId property in src/pom.xml;
  • Change the groupId property in test/pom.xml;
  • Update the applet class name in appletClass in com.vadimtch.applet_template.test.SimulatorWrapper;
• Change the applet AID:
  • Change the package.aid property in src/build.xml - this must be a colon-separated list of 5-16 hex bytes;
  • Change the applet.aid property in src/build.xml - this must start with the package AID and also be no longer than 16 bytes;
  • Update the applet AID in appletAID in com.vadimtch.applet_template.test.SimulatorWrapper;
• Rename the applet .jar and .cap files:
  • Change the package.filename property in src/build.xml - this is the filename used for the two files when creating them during a build;
  • Update the package.filename property in test/pom.xml;
• Change the JavaCard SDK version used:
  • Ensure that the JDK you are using is supported with the required SDK version (see the Set-up section for details)
  • Choose the new SDK version from the list in sdk/javacard_sdks and note its name;
  • Set the sdk.version property in src/build.xml to the directory name of the chosen SDK version, without the trailing _kit:
    • For example, to use JavaCard 3.0.5u3, set it to jc305u3;
  • Set the sdk.version property in src/pom.xml.