40、Java平台安全与杂项功能详解

Java平台安全与杂项功能详解

1. 数字签名

数字签名结合了消息摘要算法和公钥加密技术。发送方（如Alice）计算消息的摘要，然后用她的私钥对摘要进行加密。接收方（如Bob）使用发送方的公钥解密摘要，验证消息是否被篡改，同时确认消息来自发送方。

1.1 创建数字签名步骤

1. 获取私钥 ：假设系统中存在密钥库，可通过以下代码获取私钥：

// Here is some basic data we need
File homedir = new File(System.getProperty("user.home"));
File keyfile = new File(homedir, ".keystore"); // Or read from config file
String filepass = "KeyStore password";          // Password for entire file
String signer = "david";                       // Read from config file
String password = "No one can guess this!";    // Better to prompt for this
PrivateKey key;  // This is the key we want to look up from the keystore
try {
  // Obtain a KeyStore object and then l