Hidden Door Opener Server

local side = "left"
local rsSide = "right"

os.pullEvent = os.pullEventRaw

function hash(str)
  local s = 0
  local p = ""

  for c in str:gmatch(".") do
      s = s + string.byte(c)
  end

  s = bit.bxor(65432895, s)

  while s > 0 do
      p = p .. string.char(s % 94 + 33)
      s = bit.brshift(s, 1)
  end

  return string.sub(p, 1, p:len() - 1)
end

rednet.open(side)

term.clear()
term.setCursorPos(1, 1)

term.setTextColor(colors.blue)

term.write("Hidden Door opener running on " .. side)

while true do
  id, msg = rednet.receive()

  if not string.sub(msg, 1, 3) == "hd:" then return end

  if hash(string.sub(msg, 4, string.len(msg))) == "~08[mvK6+Ujty|N7[>^?_@0($" then
    rs.setOutput(rsSide, true)
    sleep(3)
    rs.setOutput(rsSide, false)
  end
end