java结合keytool如何实现非对称加密与解密详解

$ keytool -genkey -alias signLegal -keystore examplestanstore2 -validity 1800 -keyalg RSA

$ keytool -list -keystore examplestanstore2 -v

$ keytool -export -keystore examplestanstore2 -alias signLegal -file StanSmith.crt -rfc

import java.io.*;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import javax.crypto.Cipher;
import sun.security.provider.*;


public class RSAEntry {
 public static void main(String[] args) {
 try {
 //1.从密钥库中取私钥
 KeyStore ks = KeyStore.getInstance("JKS");
 FileInputStream ksfis = new FileInputStream("examplestanstore2");
 BufferedInputStream ksbufin = new BufferedInputStream(ksfis);

 // open keystore and get private key
 // alias is 'signLeal', kpasswd/spasswd is 'vagrant'
 ks.load(ksbufin, "vagrant".toCharArray());
 PrivateKey prikey = (PrivateKey) ks.getKey("signLegal", "vagrant".toCharArray());

 //2.根据命令行参数取公钥
 FileInputStream certfis = new FileInputStream(args[0]);
 java.security.cert.CertificateFactory cf =
  java.security.cert.CertificateFactory.getInstance("X.509");
 java.security.cert.Certificate cert = cf.generateCertificate(certfis);
 PublicKey pubKey = cert.getPublicKey();


 //3.使用公钥进行加密
 String data = "测试数据";
 //构建加密解密类
 Cipher cipher = Cipher.getInstance("RSA");
 cipher.init(Cipher.ENCRYPT_MODE, pubKey);//设置为加密模式
 byte[] jmdata = cipher.doFinal(data.getBytes());
 //打印加密后数据
 System.out.println(bytesToHexString(jmdata));
 //改为解密模式进行解密
 cipher.init(Cipher.DECRYPT_MODE, prikey);//会用私钥解密
 jmdata = cipher.doFinal(jmdata);
 System.out.println(new String(jmdata));
 }catch (Exception e) {
  e.printStackTrace();
 }
 }
 //这个方法用于把二进制转换成ASCII字符串。
 public static String bytesToHexString(byte[] bytes) {
 if (bytes == null)
  return "null!";
 int len = bytes.length;
 StringBuilder ret = new StringBuilder(2 * len);

 for (int i = 0; i < len; ++i) {
  int b = 0xF & bytes[(i)] >> 4;
  ret.append("0123456789abcdef".charAt(b));
  b = 0xF & bytes[(i)];
  ret.append("0123456789abcdef".charAt(b));
 }

 return ret.toString();
 }
}

$ javac RSAEntry.java
$ java RSAEntry StanSmith.crt
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
测试数据