JavaCard Hardware Wallet

The status.im Hardware Wallet. At the moment Secure Channel and PIN management/verification are implemented.

The project is built using Gradle with the Fidesmo Javacard Gradle plugin. You can set the JavaCard HOME not only through the environment but also creating a gradle.properties file with the property "com.fidesmo.gradle.javacard.home" set to the correct path.

Loading and installing the applet requires gpshell to be installed on the system. The gradle.properties file must contain the following properties

• im.status.gradle.gpshell = the path to the gpshell executable
• im.status.gradle.gpshell.isd = the AID of the issuer security domain
• im.status.gradle.gpshell.mac_key = the MAC key for the ISD
• im.status.gradle.gpshell.enc_key = the ENC key for the ISD
• im.status.gradle.gpshell.kek_key = the KEK key for the ISD
• im.status.gradle.gpshell.kvn = the Key Version Number for the ISD

Testing is done with JUnit and performed either on a real card or on jCardSim. Although the tests are comprehensive, debugging on the real card is not easy because raw APDUs are not shown in the test log and there is no way to set breakpoints in the applet.

In order to test with the simulator, you need to pass these additional parameters to the JVM

-noverify -Dim.status.wallet.test.simulated=true

Compilation

1. Download and install the JavaCard 3.0.4 SDK from Oracle
2. Clone the Github repo for our fork of jCardSim
3. Create a gradle.properties (see below for an example)
4. Run ./gradlew build

Example gradle.properties file

com.fidesmo.gradle.javacard.home=/home/username/javacard-3_0_4
im.status.gradle.gpshell=/usr/local/bin/gpshell
im.status.gradle.gpshell.isd=A000000003000000
im.status.gradle.gpshell.mac_key=404142434445464748494a4b4c4d4e4f
im.status.gradle.gpshell.enc_key=404142434445464748494a4b4c4d4e4f
im.status.gradle.gpshell.kek_key=404142434445464748494a4b4c4d4e4f
im.status.gradle.gpshell.kvn=2

Implementation notes

• The applet requires JavaCard 3.0.4 or later.
• The class byte of the APDU is not checked since there are no conflicting INS code.
• Automated tests using JUnit 5 are included. The test require the application to be already installed. The first card terminal found by Java will be used, to please disconnect all card terminals except the one to be used for testing.