Implementing Your Own Permission

Steps for the TerrysGame Developer (Terry)

The steps Terry would take, after creating a game (TerrysGame ) that calls the HighScore getHighScore and setHighScore methods to get and set, respectively, the user's high scores, are:

Compile the Game Class

javac TerrysGame.java

Place its class file in a JAR File

jar cvf terry.jar TerrysGame.class

Create a Keystore and Keys for Signing

keytool -genkey -keystore terry.keystore -alias signTJars

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

Sign the JAR File

jarsigner -keystore terry.keystore terry.jar signTJars

Export the Public Key Certificate

keytool -export -keystore terry.keystore -alias signTJars -file Terry.cer

Supply Files and Information Needed by Users

That is, supply them

• the signed JAR File terry.jar,

• the public key certificate file Terry.cer, and

• information as to the permissions the TerrysGame class needs. For this, Terry could supply the exact grant entry needed.

Game users also need files and information from Chris. For their convenience, Terry may forward this information to 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. This could be the exact grant entry needed.

Implementing Your Own Permission