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Trail: Security Features in Java SE
Lesson: Signing Code and Granting It Permissions
Section: Steps for the Code Signer
Signing Code and Granting It Permissions
Steps for the Code Signer
Download and Try the Sample Application
Create a JAR File Containing the Class File
Generate Keys
Sign the JAR File
Export the Public Key Certificate
Steps for the Code Receiver
Observe the Restricted Application
Import the Certificate as a Trusted Certificate
Set Up a Policy File to Grant the Required Permission
Start Policy Tool
Specify the Keystore
Add a Policy Entry with a SignedBy Alias
Save the Policy File
See the Policy File Effects
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Download and Try the Sample Application

> This lesson uses a simple application that we provide to you.

> 1. Create a file named `Count.java` on your local computer by either copying or downloading the `Count.java` source code. The examples in this lesson assume that you place `count` in the `C:\Test` directory.
> 2. The `count` application needs to access a text file containing the data it will process. Download a sample data file here, or use any other convenient text file as data.

>    Important: Put your data file into a directory other than the directory containing your downloaded `count` class file. We suggest `C:\TestData\data`.
>    Later in this lesson you will see how an application running under a security manager cannot read a file unless it has explicit permission to do so. However, an application can always read a file from the same directory (or a subdirectory). It does not need explicit permission.

> 3. Compile and then run the `Count` application to see what it does.
>    When you run the `count` application, you need to specify (as an argument) the path name of a file to be read.
>    `java Count C:\TestData\data
>    `

> Here is a sample run:

>         C:\Test>java Count C:\TestData\data
>         Counted 65 chars.

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