local function tostr(bts)
  local str = ""
  for k, v in pairs(bts) do
    if type(v) == "number" then
      str = str..string.char(v)
    end
  end
  return str
end
local function tobits(str)
  local rtrntbl = {}
  for char in string.gmatch(str, ".") do
    rtrntbl[#rtrntbl+1] = string.byte(char)
  end
  return rtrntbl
end 
local function mkKey(key)
  local key = tostring(key)
  local str = ""
  for char in string.gmatch(key, ".") do
    str = str..tostring(string.byte(char))
  end
  return str
end
local function sepkey(key)
  local key = tostring(key)
  local ky = {}
  for char in string.gmatch(key, ".") do
    ky[#ky+1] = tonumber(char)
  end
  return ky
end
local function enc(keyo, str1)
  local str2 = tobits(str1)
  local key = sepkey(mkKey(keyo))
  local num = 0
  for k, v in pairs(str2) do
    num = num+1
    if num > #key then
      num = 1
    end
    if v+key[num] > 255 then
      str2[k] = v+key[num]-255
    else
      str2[k] = v+key[num]
    end
  end
  str2 = tostr(str2)
  return str2
end
function encrypt(key, str)
  local keyn = sepkey(mkKey(key))
  keyn = keyn[#keyn-1]
  local rtrn
  local cnt = 0
  for i = 1, string.byte(keyn) do
    cnt = cnt+1
    rtrn = enc(key, str)
    if cnt == 100 then
      cnt = 0
      sleep(0)
    end
  end
  return rtrn
end
local function dec(keyo, str1)
  local str2 = tobits(str1)
  local key = sepkey(mkKey(keyo))
  local num = 0
  for k, v in pairs(str2) do
    num = num+1
    if num > #key then
      num = 1
    end
    if v+key[num] < 0 then
      str2[k] = v-key[num]+255
    else
      str2[k] = v-key[num]
    end
  end
  str2 = tostr(str2)
  return str2
end
function decrypt(key, str)
  local keyn = sepkey(mkKey(key))
  keyn = keyn[#keyn-1]
  local rtrn
  local cnt = 0
  for i = 1, string.byte(keyn) do
    cnt = cnt+1
    rtrn = dec(key, str)
    if cnt == 100 then
      cnt = 0
      sleep(0)
    end
  end
  return rtrn
end

local readdir = function(path)
	if fs.isDir(path) then
		return false, "cannot read directory"
	end
	local file = fs.open(path,"r")
	if file then
		local cont = file.readAll()
		return cont
	else
		return false, "no such file"
	end
end

local writetopath = function(path,str)
	if fs.isDir(path) then
		return false, "cannot write to existing directory"
	end
	local file = fs.open(path,"w")
	file.write(str)
	file.close()
end

function encryptFile(key,path)
	return writetopath(path,encrypt(key,readdir(path)))
end
function decryptFile(key,path)
	return writetopath(path,decrypt(key,readdir(path)))
end