Not every byte of a file, and reverse the filename.

NotFile

using System;
using System.IO;

namespace NotFile
{
    class Program
    {
        static void Main(string[] args)
        {
            foreach (string path in args)
                if (File.Exists(path))
                {
                    FileInfo fi = new FileInfo(path);
                    using (FileStream fsIn = new FileStream(path, FileMode.Open))
                        using (FileStream fsOut = new FileStream(Path.Combine(fi.DirectoryName, ReverseString(fi.Name)), FileMode.Create))
                        {
                            fsIn.Position = 0;
                            int i = 0;
                            while ((i = fsIn.ReadByte()) != -1)
                                fsOut.WriteByte((byte)(~(byte)i));
                        }
                }
        }
        static string ReverseString(string s)
        {
            string o = "";
            for (int i = 0; i < s.Length; i++)
                o = s[i] + o;
            return o;
        }
    }
}