using System;
using System.Security.Cryptography;
using System.IO;
using System.Text;

namespace Mtxfw.Utility
{
    public class Security
    {
        static int key = 20200608;
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="decryptString"></param>
        /// <returns></returns>
        public static string DecryptString(string decryptString)
        {
            if (decryptString != "")
            {
                string str = "解密字符失败!";
                try
                {

                    SymmetricAlgorithm algorithm = SymmetricAlgorithm.Create("TripleDES");
                    algorithm.Mode = CipherMode.ECB;
                    algorithm.Key = Encoding.UTF8.GetBytes(splitStringLen("encrypt52ttxfw", 0x18, '0'));
                    algorithm.Padding = PaddingMode.PKCS7;
                    ICryptoTransform transform = algorithm.CreateDecryptor();
                    byte[] buffer = Convert.FromBase64String(decryptString);
                    MemoryStream stream = new MemoryStream();
                    CryptoStream stream2 = new CryptoStream(stream, transform, CryptoStreamMode.Write);
                    try
                    {
                        stream2.Write(buffer, 0, buffer.Length);
                        stream2.FlushFinalBlock();
                        str = Encoding.UTF8.GetString(stream.ToArray());
                    }
                    catch (Exception exception)
                    {
                        str = exception.ToString();
                    }
                    finally
                    {
                        stream.Close();
                        stream2.Close();
                        stream.Dispose();
                        stream2.Dispose();
                        transform.Dispose();
                        algorithm.Clear();
                    }
                }
                catch (Exception exception2)
                {
                    str = decryptString;
                }
                return str;
            }
            else
            {
                return decryptString;
            }
        }

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="encryptValue"></param>
        /// <returns></returns>
        public static string EncryptString(string encryptValue)
        {

            if (encryptValue != "")
            {
                string str = "加密出错!";
                SymmetricAlgorithm algorithm = SymmetricAlgorithm.Create("TripleDES");
                algorithm.Mode = CipherMode.ECB;
                algorithm.Key = Encoding.UTF8.GetBytes(splitStringLen("encrypt52ttxfw", 0x18, '0'));
                algorithm.Padding = PaddingMode.PKCS7;
                ICryptoTransform transform = algorithm.CreateEncryptor();
                byte[] bytes = Encoding.UTF8.GetBytes(encryptValue);
                MemoryStream stream = new MemoryStream();
                CryptoStream stream2 = new CryptoStream(stream, transform, CryptoStreamMode.Write);
                try
                {
                    stream2.Write(bytes, 0, bytes.Length);
                    stream2.FlushFinalBlock();
                    str = Convert.ToBase64String(stream.ToArray());
                }
                catch (Exception exception)
                {
                    str = exception.ToString();
                }
                finally
                {
                    stream2.Close();
                    stream2.Dispose();
                    stream.Close();
                    stream.Dispose();
                    algorithm.Clear();
                    transform.Dispose();
                }
                return Convert.ToBase64String(stream.ToArray());
            }
            else
            {
                return encryptValue;
            }
        }

        private static string splitStringLen(string s, int len, char b)
        {
            if (string.IsNullOrEmpty(s))
            {
                return "";
            }
            if (s.Length >= len)
            {
                return s.Substring(0, len);
            }
            return s.PadRight(len, b);
        }
        // 加密算法可以公开
        public static int encrypt(int plainText)
        {
            return plainText ^ key;
        }

        // 解密算法也可以公开
        public static int decrypt(int cipherText)
        {
            return cipherText ^ key;
        }
    }
}