package com.itmuch.cloud.util;
import org.apache.tomcat.util.codec.binary.Base64;
import javax.crypto.Cipher;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
/**
* 功能描述,RSA生成私鑰公鑰加解密工具類
* @author:mischen
* @date:2020/4/5 17:19
*/
public class RSAUtils {
private static Map<Integer, String> keyMap = new HashMap<Integer, String>(); //用於封裝隨機產生的公鑰與私鑰
public static void main(String[] args) throws Exception {
//生成公鑰和私鑰
genKeyPair();
//加密字符串
String message = "mischen.14588@";
System.out.println("隨機生成的公鑰爲:" + keyMap.get(0));
System.out.println("隨機生成的私鑰爲:" + keyMap.get(1));
//用公鑰進行加密
String messageEn = encrypt(message,keyMap.get(0));
System.out.println(message + "\t加密後的字符串爲:" + messageEn);
//用私鑰進行解密
String messageDe = decrypt(messageEn,keyMap.get(1));
System.out.println("還原後的字符串爲:" + messageDe);
}
/**
* 隨機生成密鑰對
* @throws NoSuchAlgorithmException
*/
public static void genKeyPair() throws NoSuchAlgorithmException {
// KeyPairGenerator類用於生成公鑰和私鑰對,基於RSA算法生成對象
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
// 初始化密鑰對生成器,密鑰大小爲96-1024位
keyPairGen.initialize(1024,new SecureRandom());
// 生成一個密鑰對,保存在keyPair中
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); // 得到私鑰
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 得到公鑰
String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
// 得到私鑰字符串
String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
// 將公鑰和私鑰保存到Map
keyMap.put(0,publicKeyString); //0表示公鑰
keyMap.put(1,privateKeyString); //1表示私鑰
}
/**
* RSA公鑰加密
*
* @param str
* 加密字符串
* @param publicKey
* 公鑰
* @return 密文
* @throws Exception
* 加密過程中的異常信息
*/
public static String encrypt( String str, String publicKey ) throws Exception{
//base64編碼的公鑰
byte[] decoded = Base64.decodeBase64(publicKey);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
//RSA加密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
return outStr;
}
/**
* RSA私鑰解密
*
* @param str
* 加密字符串
* @param privateKey
* 私鑰
* @return 銘文
* @throws Exception
* 解密過程中的異常信息
*/
public static String decrypt(String str, String privateKey) throws Exception{
//64位解碼加密後的字符串
byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
//base64編碼的私鑰
byte[] decoded = Base64.decodeBase64(privateKey);
RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
//RSA解密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, priKey);
String outStr = new String(cipher.doFinal(inputByte));
return outStr;
}
}