10 Security and MIDlet Signing

10.1 Security Domains

The SDK supports the following security domains:

minimum. All permissions are denied to MIDlets in this domain.

maximum. All permissions are granted to MIDlets in this domain. Maximum is the default setting.

unidentified_third_party. Provides a high level of security for applications whose origins and authenticity cannot be determined. The user is prompted frequently when the application attempts a sensitive operation.

identified_third_party. Intended for MIDlets whose origins were determined using cryptographic certificates. Permissions are not granted automatically, but the user is prompted less often than for the unidentified_third_party domain.

operator. All permissions are denied to MIDlets in this domain.

manufacturer. Intended for MIDlet suites whose credentials originate from the manufacturer's root certificate.

10.2 Setting Security Domains

In the SDK, when you use Run Project via OTA your packaged MIDlet suite is installed directly into the emulator where it is placed in a security domain. The emulator uses public key cryptography to determine the appropriate security domain.

• If the MIDlet or MIDlet suite is not signed, it is placed in the default security domain.

• If the MIDlet or MIDlet suite is signed, it is placed in the protection domain that is associated with the root certificate of the signing key's certificate chain. See Section 10.3, "Signing a Project With a Key Pair."

  If your project is a MIDlet suite, the entire suite is signed (the individual MIDlets contained within are not).

10.3 Signing a Project With a Key Pair

Devices use signing information to check an application's source and validity before allowing it to access protected APIs. For test purposes, you can create a signing key pair to sign an application. A key pair consists of the following:

• A private key that is used to create a digital signature, or certificate.

• A public key that anyone can use to verify the authenticity of the digital signature.

You can create a key pair as described in Section 10.4, "Managing Keystores and Key Pairs."

Follow these steps to sign a Java ME package in Eclipse.

1. In the Package view right-click on a package and select Properties to open the Properties dialog.

2. In the Java ME category, select Signing. For help with this page, view the following help topic: Java ME Development User Guide > Reference > Property Pages > Java ME.

3. Click Enable project specific settings. Specify a keystore and a password option.

4. Click OK.

To obfuscate code, see Section 4.4.4, "Obfuscating."

10.4 Managing Keystores and Key Pairs

The Oracle Java ME SDK command line tools described in Section 11.6.3, "Manage Certificates (MEKeyTool)" manage an emulator's list of root certificates.

Oracle Java ME SDK ships a default keystore named _main.ks in installdir\runtimes\cldc-hi\appdb. This keystore is automatically copied from your installation's default location to each instance of the default devices (the emulators). These instances are typically stored in:

C:\Documents and Settings\username\javame-sdk\3.2\work\devicename

Real devices have similar lists of root certificates, although you typically cannot modify them. When you deploy your application on a real device, you must use signing keys issued by a certificate authority whose root certificate is present on the device. This makes it possible for the device to verify your application.

In Eclipse you can also use MTJ utilities to manage keystores as described in Section 10.3, "Signing a Project With a Key Pair." You can also use the -import option to import certificates from these keystores as described in Section 11.6.3, "Manage Certificates (MEKeyTool)."

10.5 Command Line Samples

This section is a summary of command line samples for keystore and certificate tasks. For the full syntax of keytool, see: http://docs.oracle.com/javase/7/docs/technotes/tools/solaris/keytool.html

These samples show literal paths on a sample system. You can replace the paths and options as you see fit. These samples contain linefeeds to accommodate the book format. In practice they commands should be entered on a single line.

Generate a keypair.

As mentioned in Section 10.4, "Managing Keystores and Key Pairs," Java ME includes a default keystore used for the emulators. For test purposes you can also make your own keypair containing a new keystore and a certificate. For example:

"C:\Program Files\Java\jdk1.6.0_35\bin\keytool" -genkeypair -alias mykp 
-keyalg RSA -keysize 1024 -validity 365 -dname "cn=dlp, L=Santa Clara, S=CA"
-keypass 123456 -keystore D:/temp/mykeystore.ks -storepass 654321

List the keypair.

C:\Progra~1\Java\jdk1.6.0_35\bin\keytool -list -alias mykp 
-keystore mykeystore.ks -storepass 654321

Export a certificate to a file.

C:\Progra~1\Java\jdk1.6.0_35\bin\keytool -exportcert -alias mykp 
-keystore mykeystore.ks -storepass 654321 -file d:\temp\mykpcert

Print the certificate file.

C:\Progra~1\Java\jdk1.6.0_35\bin\keytool -printcert -file d:\temp\mykpcert

Import the keystore (including your certificate) into the default keystore.

For a description of MEKeyTool, see Section 11.6.3, "Manage Certificates (MEKeyTool)." In this example mekeytool is launched from the Java ME SDK installation bin directory.

mekeytool -import -alias mykp -keystore D:\temp\mykeystore.ks -MEkeystore D:\temp\_main.ks -storepass 654321