.net core使用MD5加密解密字符串

/// <summary>
 /// 加密
 /// </summary>
 /// <param name="Text">要加密的文本</param>
 /// <param name="sKey">秘钥</param>
 /// <returns></returns>
 public static string Encrypt(string Text, string sKey="test")
 {
 DESCryptoServiceProvider des = new DESCryptoServiceProvider();
 byte[] inputByteArray;
 inputByteArray = Encoding.Default.GetBytes(Text);
 des.Key = ASCIIEncoding.ASCII.GetBytes(Md5Hash(sKey).Substring(0,8));
 des.IV = ASCIIEncoding.ASCII.GetBytes(Md5Hash(sKey).Substring(0, 8));
 System.IO.MemoryStream ms = new System.IO.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);
 }
 md4j= ret.ToString();
 return ret.ToString();
 }

/// <summary>
 /// 解密
 /// </summary>
 /// <param name="Text"></param>
 /// <param name="sKey"></param>
 /// <returns></returns>
 public static string Decrypt(string Text, string sKey = "test")
 {
 DESCryptoServiceProvider des = new DESCryptoServiceProvider();
 int len;
 len = Text.Length / 2;
 byte[] inputByteArray = new byte[len];
 int x, i;
 for (x = 0; x < len; x++)
 {
 i = Convert.ToInt32(Text.Substring(x * 2, 2), 16);
 inputByteArray[x] = (byte)i;
 }
 des.Key = ASCIIEncoding.ASCII.GetBytes(Md5Hash(sKey).Substring(0, 8));
 des.IV = ASCIIEncoding.ASCII.GetBytes(Md5Hash(sKey).Substring(0, 8));
 System.IO.MemoryStream ms = new System.IO.MemoryStream();
 CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
 cs.Write(inputByteArray, 0, inputByteArray.Length);
 cs.FlushFinalBlock();
 return Encoding.Default.GetString(ms.ToArray());
 }

/// <summary>
 /// 32位MD5加密
 /// </summary>
 /// <param name="input"></param>
 /// <returns></returns>
 private static string Md5Hash(string input)
 {
 MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider();
 byte[] data = md5Hasher.ComputeHash(Encoding.Default.GetBytes(input));
 StringBuilder sBuilder = new StringBuilder();
 for (int i = 0; i < data.Length; i++)
 {
 sBuilder.Append(data[i].ToString("x2"));
 }
 return sBuilder.ToString();
 }

public static string md4j = "";
static void Main(string[] args)
 {
 //加密
 Encrypt("123456");
 Decrypt(md4j);
 }