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

namespace RoadFlow.Utility
{
    /// <summary>
    /// 加解密类
    /// </summary>
    public class Encryption
    {
        /// <summary>
        /// 字符串MD5加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string MD5(string str)
        {
            var md5 = System.Security.Cryptography.MD5.Create();
            var result = md5.ComputeHash(Encoding.UTF8.GetBytes(str));
            var strResult = BitConverter.ToString(result);
            return strResult.Replace("-", "");
        }

        /// <summary>
        /// 字符串SHA1加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string SHA1(string str)
        {
            var sha1 = System.Security.Cryptography.SHA1.Create();
            var result = sha1.ComputeHash(Encoding.UTF8.GetBytes(str));
            var strResult = BitConverter.ToString(result);
            return strResult.Replace("-", "");
        }

        /// <summary>
        /// 加密KEY
        /// </summary>
        private static readonly string encryptKey = "4h!@w$rn";

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="encryptString"></param>
        /// <returns></returns>
        public static string DESEncrypt(string encryptString)
        {
            try
            {
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                byte[] inputByteArray;
                inputByteArray = Encoding.Default.GetBytes(encryptString);
                string md5SKey = encryptKey;
                des.Key = Encoding.ASCII.GetBytes(md5SKey);
                des.IV = Encoding.ASCII.GetBytes(md5SKey);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                StringBuilder ret = new StringBuilder();
                foreach (byte b in ms.ToArray())
                {
                    ret.AppendFormat("{0:X2}", b);
                }
                return ret.ToString();
            }
            catch { return ""; }
        }
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="decryptString"></param>
        /// <returns></returns>
        public static string DESDecrypt(string decryptString)
        {
            try
            {
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                int len;
                len = decryptString.Length / 2;
                byte[] inputByteArray = new byte[len];
                int x, i;
                for (x = 0; x < len; x++)
                {
                    i = Convert.ToInt32(decryptString.Substring(x * 2, 2), 16);
                    inputByteArray[x] = (byte)i;
                }
                string md5SKey = encryptKey;
                des.Key = Encoding.ASCII.GetBytes(md5SKey);
                des.IV = Encoding.ASCII.GetBytes(md5SKey);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                return Encoding.Default.GetString(ms.ToArray());
            }
            catch { return ""; }
        }
    }
}