File To MD5, SHA1, SHA256, SHA512 in C#

        string stMD5="";
        string stSHA1="";
        string stSHA256="";
        string stSHA512="";

        private void  ToMD5(string FilePath)
        {
            //tạo đối tượng mã hóa MD5
            MD5 MyMD5 = MD5.Create();
            //đọc file
            FileStream fs = new FileStream(FilePath, FileMode.Open);
            //mã hóa mảng byte bằng MD5
            byte[] HashCode = MyMD5.ComputeHash(fs);
            //chuyển mảng byte thành chuỗi
            StringBuilder SB = new StringBuilder();
            for (int i = 0; i < HashCode.Length; i++)
                SB.Append(HashCode[i].ToString("x2"));
            stMD5 =SB.ToString();

            fs.Close();

        }
        private void  ToSHA1(string FilePath)
        {
            //tạo đối tượng mã hóa SHA1
            SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
            //đọc file
            FileStream fs = new FileStream(FilePath, FileMode.Open);
            //mã hóa mảng byte bằng sha1
            byte[] HashCode = sha1.ComputeHash(fs);
            //chuyển mảng byte thành chuỗi
            StringBuilder SB = new StringBuilder();
            for (int i = 0; i < HashCode.Length; i++)
                SB.Append(HashCode[i].ToString("x2"));
             stSHA1=SB.ToString();
             fs.Close();

        }
        private void  ToSHA256(string FilePath)
        {
            //Tao doi tuong ma hoa sha 256
            SHA512CryptoServiceProvider sha1 = new SHA512CryptoServiceProvider();
            //Doc file
            FileStream fs = new FileStream(FilePath, FileMode.Open);
            //ma hoa mang byte bang sha 256

            byte[] HashCode = sha1.ComputeHash(fs);
            //Chuyen kieu byte sang kieu chuoi
            StringBuilder SB = new StringBuilder();
            for (int i = 0; i < HashCode.Length; i++)
                SB.Append(HashCode[i].ToString("x2"));
            stSHA256=SB.ToString();
            fs.Close();
        }
        private void  ToSHA512(string FilePath)
        {
           //Tao doi tuong ma hoa sha 512
            SHA512CryptoServiceProvider sha1 = new SHA512CryptoServiceProvider();
            //Mo file
            FileStream fs = new FileStream(FilePath, FileMode.Open);
           // ma hoa mang byte bang sha 512
            byte[] HashCode = sha1.ComputeHash(fs);
            //Chuyen kieu byte sang kieu String
            StringBuilder SB = new StringBuilder();
            for (int i = 0; i < HashCode.Length; i++)
                SB.Append(HashCode[i].ToString("x2"));
           stSHA512=SB.ToString();
           fs.Close();
        }