package com.tuoheng.admin.utils;

import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import java.util.Base64;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
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;

/**
 * Java RSA 加密工具类
 *
 */
public class RSAUtils {

    /**
     * 密钥长度 于原文长度对应 以及越长速度越慢
     */
    private final static int KEY_SIZE = 1024;

    /**
     * 用于封装随机产生的公钥与私钥
     */
    private static Map<Integer, String> keyMap = new HashMap<Integer, String>();

    /**
     * 随机生成密钥对
     */
    public static void genKeyPair() throws NoSuchAlgorithmException {
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        // 初始化密钥对生成器
        keyPairGen.initialize(KEY_SIZE, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();
        // 得到私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        // 得到公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        String publicKeyString = Base64.getEncoder().encodeToString(publicKey.getEncoded());
        // 得到私钥字符串
        String privateKeyString = Base64.getEncoder().encodeToString(privateKey.getEncoded());
        // 将公钥和私钥保存到Map
        //0表示公钥
        keyMap.put(0, publicKeyString);
        //1表示私钥
        keyMap.put(1, privateKeyString);
    }

    /**
     * RSA公钥加密
     *
     * @param str       加密字符串
     * @param publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String str, String publicKey) {
        //base64编码的公钥
        byte[] decoded = Base64.getDecoder().decode(publicKey);
        //RSA加密
        Cipher cipher = null;
        try {
            RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
            cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, pubKey);
            String outStr = Base64.getEncoder().encodeToString(cipher.doFinal(str.getBytes("UTF-8")));
            return outStr;
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        } catch (NoSuchPaddingException e) {
            throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
            throw new RuntimeException(e);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        } catch (BadPaddingException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeySpecException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * RSA私钥解密
     *
     * @param str        加密字符串
     * @param privateKey 私钥
     * @return 明文
     * @throws Exception 解密过程中的异常信息
     */
    public static String decrypt(String str, String privateKey) throws Exception {
        //64位解码加密后的字符串
        byte[] inputByte = Base64.getDecoder().decode(str);
        //base64编码的私钥
        byte[] decoded = Base64.getDecoder().decode(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;
    }

    public static void main(String[] args) throws Exception {
//        long temp = System.currentTimeMillis();
//        //生成公钥和私钥
//        genKeyPair();
//        //加密字符串
//        System.out.println("公钥:" + keyMap.get(0));
//        System.out.println("私钥:" + keyMap.get(1));
//        System.out.println("生成密钥消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
//        //客户id + 授权时间 + 所用模块
//        String message = "4028138151b3cf300151b419df090007" + "2015-12-17 11:30:22" + "A01,A02";
//        System.out.println("原文:" + message);
//        temp = System.currentTimeMillis();
//        //通过原文，和公钥加密。
//        String messageEn = encrypt(message, keyMap.get(0));
//        System.out.println("密文:" + messageEn);
//        System.out.println("加密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
//        temp = System.currentTimeMillis();
//        //通过密文，和私钥解密。
//        String messageDe = decrypt(messageEn, keyMap.get(1));
//        System.out.println("解密:" + messageDe);
//        System.out.println("解密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");

        String str = encrypt("sef$dFw7@xxfg", "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAi/HYqCsLgSG2ZGYMAmK2eG8oAm3Xi+zf0pEbNlhZwfoYMx1syXrlHGVbiYam3UScIHNlr4OF2jqDZFpNoj0HjNnsNZUfpSjokjJeTu5sI5R+sUDKFBjjsWu5nrrcl6ae+6Y0E5lhPbowzT+ZWiLQl9fx2+7YuR1F/bGAl2WSBQh/GeKN7HbxYfwSTquRYcHYLwC/WVUOUP04BsTmgGN7NJ/BCjg4rpgY57BD2D756u3sIDRjWyaI6my69xZ9tGfR7rmd+qxPVZsRcJOY9Vk5PjcYwMPNwGVg3WT6yAmPZwrBEJb4KvGDqdZnHqvlmjryxVEgLs2Som7VZEK461fd7wIDAQAB");

        System.out.println(str);
    }
}