java 中RSA的方式实现非对称加密的实例

java 中rsa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：

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： 

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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