The steps Chris would take, after creating the HighScore and HighScorePermission classes, are:

Compile the Classes

javac HighScore*.java -d .

Place the class files in a JAR File

jar cvf hs.jar com/scoredev/scores/HighScore*.class

Create a Keystore and Keys for Signing

keytool -genkey -keystore chris.keystore -alias signJars

Specify whatever you want for the passwords and distinguished name information.

Sign the JAR File

jarsigner -keystore chris.keystore hs.jar signJars

Export the Public Key Certificate

keytool -export -keystore chris.keystore
    -alias signJars -file Chris.cer

Supply Files and Information Needed by Game Developers and Users

That is, supply them

• the signed JAR File hs.jar,

• the public key certificate file Chris.cer, and

• information as to the permissions the HighScore and HighScorePermission classes must be granted in a policy file in order to work. For this, Chris could supply the exact grant entry needed.