java 中RSA的方式实现非对称加密的实例

时间:2021-08-26 05:28:07

javaRSA的方式实现非对称加密的实例

RSA通俗理解:

你只要去想:既然是加密,那肯定是不希望别人知道我的消息,所以只有我才能解密,所以可得出公钥负责加密,私钥负责解密;同理,既然是签名,那肯定是不希望有人冒充我发消息,只有我才能发布这个签名,所以可得出私钥负责签名,公钥负责验证。

实现代码:

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package com.sahadev;
 
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
 
import javax.crypto.Cipher;
 
import org.apache.commons.codec.binary.Base64;
 
public class RSA {
 
  public static void main(String[] args) {
    JDKRSA();
  }
 
  public static void JDKRSA() {
    try {
      // 构建密钥对儿
      KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
      keyPairGenerator.initialize(512);
      KeyPair keyPair = keyPairGenerator.generateKeyPair();
      RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
      RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
      System.out.println("Public Key : " + org.apache.commons.codec.binary.Base64.encodeBase64String(rsaPublicKey.getEncoded()));
      System.out.println("Private Key : " + org.apache.commons.codec.binary.Base64.encodeBase64String(rsaPrivateKey.getEncoded()));
 
      // 2.私钥加密,公钥解密---加密
      PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
      KeyFactory keyFactory = KeyFactory.getInstance("RSA");
      PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
      Cipher cipher = Cipher.getInstance("RSA");
      cipher.init(Cipher.ENCRYPT_MODE, privateKey);
      byte[] result = cipher.doFinal(DH.src.getBytes());
      System.out.println("私钥加密,公钥解密------加密 : " + Base64.encodeBase64String(result));
 
      // 3.私钥加密,公钥解密---解密
      X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
      keyFactory = KeyFactory.getInstance("RSA");
      PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
      cipher = Cipher.getInstance("RSA");
      cipher.init(Cipher.DECRYPT_MODE, publicKey);
      result = cipher.doFinal(result);
      System.out.println("私钥加密,公钥解密------解密 : " + new String(result));
 
      // 4.公钥加密,私钥解密---加密
      x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
      keyFactory = KeyFactory.getInstance("RSA");
      publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
      cipher = Cipher.getInstance("RSA");
      cipher.init(Cipher.ENCRYPT_MODE, publicKey);
      result = cipher.doFinal(DH.src.getBytes());
 
      System.out.println("公钥加密,私钥解密------加密 : " + Base64.encodeBase64String(result));
 
      // 5.公钥加密,私钥解密---解密
      pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
      keyFactory = KeyFactory.getInstance("RSA");
      privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
      cipher = Cipher.getInstance("RSA");
      cipher.init(Cipher.DECRYPT_MODE, privateKey);
      result = cipher.doFinal(result);
      System.out.println("公钥加密,私钥解密------解密 : " + new String(result));
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

附上输出结果: 

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Public Key : MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAJcFshoP5xm94r2aTbe++aMZMzJtXHxDpqmMQ9aL1cEthr2Xtac+Eckv32Kzb4R8C/6vObNBfd8sWx9FU5N2y6cCAwEAAQ==
Private Key : MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAlwWyGg/nGb3ivZpNt775oxkzMm1cfEOmqYxD1ovVwS2GvZe1pz4RyS/fYrNvhHwL/q85s0F93yxbH0VTk3bLpwIDAQABAkBdAA7rabug6IRGykztyFcmjxAuD5aSl358jnoAFuCtMo4skfxh1vR4ENFUE0Lt0zJ3CKVH0o9UQDNG0r4jeOGRAiEA3KuXps9OG0AXuxLggg0e7B1Os5C3gNrH2fMqAPjtpY0CIQCvM4EPfdrjjNQiM0ATVBT5jZnw3PRu33pdyISWuoMHAwIgDOLMSUZjxj2Y5Si2CYIgoyMW/G9f99tOvlBvzHy8y+UCIF94MVu/uQdGNlJsmv3tU4CpKLmXrZq9LHDuU1HPUJcBAiEAy/0OS2Q9EBfmPwhsGXF4WMxj4wG0xzNFWxSeZB0qxzk=
私钥加密,公钥解密------加密 : NXF87irBEmK3x/fW7IWY4GuA8AP4Rvj4DJSp2Cjjsoo5X/ScHHKdvYtlM+9TOUAvMeuKWk5WH70g53q7+E73zg==
私钥加密,公钥解密------解密 : Hello,sahadev!
公钥加密,私钥解密------加密 : hjL8928jCbNtVCRhKaYAxQNJmiIAktBskhff2I01pbaHtfGH6GJTcP1i345/3I9OzwoVFxvi/oXgVJsIsg7MOQ==
公钥加密,私钥解密------解密 : Hello,sahadev!

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原文链接:http://blog.csdn.net/sahadev_/article/details/48796057