ava加密扩展即Java Cryptography Extension，简称JCE。它是Sun的加密服务软件，包含了加密和密匙生成功能。JCE是JCA（Java Cryptography Architecture）的一种扩展。 JCE没有规定具体的加密算法，但提供了一个框架，加密算法的具体实现可以作为服务提供者加入。除了JCE框架之外，JCE软件包还包含了SunJCE服务提供者，其中包括许多有用的加密算法，比如DES（Data Encryption Standard）和Blowfish。 为简单计，在本文中我们将用DES算法加密和解密字节码。下面是用JCE加密和解密数据必须遵循的基本步骤： 步骤1：生成一个安全密匙。在加密或解密任何数据之前需要有一个密匙。密匙是随同被加密的应用一起发布的一小段数据，Listing 3显示了如何生成一个密匙。 【Listing 3：生成一个密匙】 -expansion that Java Cryptography Extension, referred to JCE. It is Sun's encryption software, including encryption and key generation functions. JCE is JCA (Java Cryptography Architecture), an extension. JCE no specific encryption algorithms, but provides a framework, the specific encryption algorithm can achieve as a service provider to join. Apart from the JCE framework, JCE package also includes SunJCE service providers, including many useful encryption algorithms such as DES (Data Encryption Standard) and the Blowfish. For simple terms, in this paper we will use DES encryption and decryption algorithms byte code. Below is JCE encryption and decryption of data must adhere to the basic steps : Step 1 : Generating a security keys. In any encryption or decryption of data is needed befo