Изменение безопасности файла

using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows.Forms;
 
namespace WindowsFormsApplication333
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
 
            var file = @"C:\test.exe:Zone.Identifier";
            WriteAlternateStream(file, @"[ZoneTransfer]\r\nZoneId=4");
        }
 
        public static void WriteAlternateStream(string path, string text)
        {
            const int GENERIC_WRITE = 1073741824;
            const int FILE_SHARE_DELETE = 4;
            const int FILE_SHARE_WRITE = 2;
            const int FILE_SHARE_READ = 1;
            const int OPEN_ALWAYS = 4;
 
            var stream = CreateFileW(path, GENERIC_WRITE, FILE_SHARE_WRITE, IntPtr.Zero, OPEN_ALWAYS, 0, IntPtr.Zero);
            using (var fs = new FileStream(stream, FileAccess.Write))
            using (var sw = new StreamWriter(fs))
                sw.Write(text);
        }
 
        [DllImport("kernel32.dll", EntryPoint = "CreateFileW")]
        public static extern System.IntPtr CreateFileW(
            [InAttribute()] [MarshalAsAttribute(UnmanagedType.LPWStr)] string lpFileName,
            uint dwDesiredAccess,
            uint dwShareMode,
            [InAttribute()] IntPtr lpSecurityAttributes,
            uint dwCreationDisposition,
            uint dwFlagsAndAttributes,
            [InAttribute()] IntPtr hTemplateFile
        );
    }
}

WriteAlternateStream(file, @"[ZoneTransfer]\r\nZoneId=4");

WriteAlternateStream(file, "[ZoneTransfer]\r\nZoneId=4");