Lesson: Signing Code and Granting It Permissions课：签名代码并授予其权限

This lesson shows how to use keytool, jarsigner, Policy Tool and jar to place files into JAR (Java ARchive) files for subsequent signing by the jarsigner tool.本课将展示如何使用keytool、jarsigner、Policy Tool和jar将文件放入jar(Java ARchive)文件中，以便jarsigner工具进行后续签名。

This lesson has two parts. First, you will create and deploy an application. Second; you will act as the recipient of a signed application.本课分为两部分。首先，您将创建并部署一个应用程序。第二；您将作为已签名申请的收件人。

Here are the steps to create and deploy an application:以下是创建和部署应用程序的步骤：

Note:  For convenience, you pretend to be a user/developer named Susan Jones. You need to define Susan Jones when you generate the keys.为了方便起见，你假装是一个名叫苏珊·琼斯的用户/开发人员。生成密钥时需要定义Susan Jones。

• Put Java class files comprising your application into a JAR file将组成应用程序的Java类文件放入JAR文件中
• Sign the JAR file签署JAR文件
• Export the public key certificate corresponding to the private key used to sign the JAR file导出用于签名JAR文件的私钥对应的公钥证书

Here are the steps to grant permissions to an application以下是向应用程序授予权限的步骤

Note:  For convenience, you pretend to be a user named Ray.为了方便起见，您可以假装是一个名为Ray的用户。

• You see how the signed application cannot normally read a file when it is run under a security manager.您可以看到，当签名的应用程序在安全管理器下运行时，它通常无法读取文件。
• Use keytool to import a certificate into Ray's keystore in an entry aliased by susan使用keytool在susan别名的条目中将证书导入到Ray的密钥库中
• Use the Policy Tool to create an entry in Ray's policy file to permit code signed by susan to read the specified file.使用策略工具在Ray的策略文件中创建一个条目，以允许susan签名的代码读取指定的文件。
• Finally, you see how the application running under a security manager can now read the file, since it has been granted permission to do so.最后，您将看到在安全管理器下运行的应用程序现在如何读取文件，因为它已被授予读取权限。

For more information about digital signatures, certificates, keystores, and the tools, see the API and Tools Use for Secure Code and File Exchanges lesson.有关数字签名、证书、密钥库和工具的更多信息，请参阅API和用于安全代码和文件交换的工具课程。

Here are the steps:以下是步骤：

• Steps for the Code Signer代码签名者的步骤
• Steps for the Code Receiver代码接收器的步骤