对称加密（AES）与非对称加密（RSA）的混合使用-CFANZ编程社区

在Java中结合使用AES（对称加密）和RSA（非对称加密）是一种常见的安全实践，既能利用AES的高效性处理大数据，又能通过RSA解决密钥分发问题。以下是混合加密的典型实现步骤和示例代码：

混合加密的核心思路

生成AES密钥：用于加密实际数据（速度快，适合大数据）。
用RSA加密AES密钥：将AES密钥通过RSA公钥加密后传输。
用AES加密数据：用AES密钥加密敏感数据。
解密时反向操作：先用RSA私钥解密得到AES密钥，再用AES解密数据。

Java实现步骤

1. 生成RSA密钥对

java
 import java.security.*;
 
  
 
 public class KeyPairGeneratorExample {
 
     public static KeyPair generateRSAKeyPair(int keySize) throws NoSuchAlgorithmException {
 
         KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
 
         keyPairGen.initialize(keySize); // 推荐2048位
 
         return keyPairGen.generateKeyPair();
 
     }
 
 }

2. 生成AES密钥

java
 import javax.crypto.KeyGenerator;
 
 import javax.crypto.SecretKey;
 
  
 
 public class AESKeyGenerator {
 
     public static SecretKey generateAESKey(int keySize) throws NoSuchAlgorithmException {
 
         KeyGenerator keyGen = KeyGenerator.getInstance("AES");
 
         keyGen.init(keySize); // 常用128/192/256位
 
         return keyGen.generateKey();
 
     }
 
 }

3. RSA加密AES密钥

java
 import javax.crypto.Cipher;
 
  
 
 public class RSAEncryptor {
 
     public static byte[] encryptAESKeyWithRSA(PublicKey publicKey, SecretKey aesKey) 
 
         throws Exception {
 
         Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
 
         cipher.init(Cipher.ENCRYPT_MODE, publicKey);
 
         return cipher.doFinal(aesKey.getEncoded());
 
     }
 
 }

4. AES加密数据

java
 public class AESEncryptor {
 
     public static byte[] encryptDataWithAES(SecretKey aesKey, byte[] data) 
 
         throws Exception {
 
         Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
 
         cipher.init(Cipher.ENCRYPT_MODE, aesKey);
 
         return cipher.doFinal(data);
 
     }
 
 }

5. 完整加密流程示例

java
 public class HybridEncryption {
 
     public static void main(String[] args) throws Exception {
 
         // 1. 生成RSA密钥对
 
         KeyPair rsaKeyPair = KeyPairGeneratorExample.generateRSAKeyPair(2048);
 
         PublicKey publicKey = rsaKeyPair.getPublic();
 
         PrivateKey privateKey = rsaKeyPair.getPrivate();
 
  
 
         // 2. 生成AES密钥
 
         SecretKey aesKey = AESKeyGenerator.generateAESKey(256);
 
  
 
         // 3. 用RSA加密AES密钥
 
         byte[] encryptedAESKey = RSAEncryptor.encryptAESKeyWithRSA(publicKey, aesKey);
 
  
 
         // 4. 用AES加密数据
 
         String originalData = "Sensitive information";
 
         byte[] encryptedData = AESEncryptor.encryptDataWithAES(aesKey, originalData.getBytes());
 
  
 
         // 5. 输出结果（实际场景需编码为Base64等格式）
 
         System.out.println("Encrypted AES Key: " + bytesToHex(encryptedAESKey));
 
         System.out.println("Encrypted Data: " + bytesToHex(encryptedData));
 
     }
 
  
 
     // 辅助方法：字节数组转十六进制字符串
 
     private static String bytesToHex(byte[] bytes) {
 
         StringBuilder sb = new StringBuilder();
 
         for (byte b : bytes) {
 
             sb.append(String.format("%02x", b));
 
         }
 
         return sb.toString();
 
     }
 
 }

解密流程

用RSA私钥解密AES密钥：

java
 public class RSADecryptor {
 
     public static SecretKey decryptAESKeyWithRSA(PrivateKey privateKey, byte[] encryptedAESKey) 
 
         throws Exception {
 
         Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
 
         cipher.init(Cipher.DECRYPT_MODE, privateKey);
 
         byte[] aesKeyBytes = cipher.doFinal(encryptedAESKey);
 
         return new SecretKeySpec(aesKeyBytes, "AES");
 
     }
 
 }

用AES解密数据：

java
 public class AESDecryptor {
 
     public static byte[] decryptDataWithAES(SecretKey aesKey, byte[] encryptedData) 
 
         throws Exception {
 
         Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
 
         cipher.init(Cipher.DECRYPT_MODE, aesKey);
 
         return cipher.doFinal(encryptedData);
 
     }
 
 }