package com.ruoyi.common.utils.rsa;

import com.alibaba.fastjson.JSONObject;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.KeyFactory;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.Date;

/**
 * token 加密工具类
 */
public class RSAPublicUtils {

    private static String publicKey = "MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAJYJcyDY6o29eo4/5AII88CnalMb8OFtLiTBWxu4UYHR5TYttHJk5dPvK/0hsAnz8WZsfP4bc8kGrA60eQIikOcCAwEAAQ==";

    /**
     * RSA公钥加密
     *
     * @param input       加密字符串
     *  publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String input) throws Exception {
        ByteArrayOutputStream bops = null;
        String encodeToString = null;
        try{
            //base64编码的公钥
            byte[] decoded = Base64.getDecoder().decode(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);
            // 标识
            byte[] bytes = input.getBytes();
            int inputLen = bytes.length;
            int offLen = 0;//偏移量
            int i = 0;
            bops = new ByteArrayOutputStream();
            while(inputLen - offLen > 0){
                byte [] cache;
                if(inputLen - offLen > 53){
                    cache = cipher.doFinal(bytes, offLen,53);
                }else{
                    cache = cipher.doFinal(bytes, offLen,inputLen - offLen);
                }
                bops.write(cache);
                i++;
                offLen = 53 * i;
            }
            bops.close();
            byte[] encryptedData = bops.toByteArray();
            encodeToString = Base64.getEncoder().encodeToString(encryptedData);
        }catch (Exception e){
            e.printStackTrace();
            throw new Exception("加密异常");
        }finally {
            if(bops != null){
                bops.close();
            }
        }
        return encodeToString;
    }

        public static void main(String[] args) throws Exception {
            JSONObject param = new JSONObject();
            param.put("userId", "1111");
            param.put("date", new Date().getTime());
            String message = param.toJSONString();
            System.out.println("原文:" + message);
            String messageEn = encrypt(message);
            System.out.println("密文:" + messageEn);
    }

}