CheckPassword

functions = {CheckPass = {{"Username"},{"Password","*"}},
  NewUser = {{"Existing user username"},
  {"Existing user password","*"},
  {"New user username"},{"New user password","*"}}}

os.loadAPI("StoreData")
rednet.open("bottom")

local function checkPass(Username,Password)
  if Username ~= nil and Password ~= nil then
    local Users = StoreData.Load("/Users")
    local password = Users[Username]
    if password ~= nil then
      if password ~= Password then
        return(false)
      else
        return(true)
      end
    else
      return(false)
    end
  end
end

local function getMessage(sender)
  running = true
  while running do
    local s,m = rednet.receive("response")
    if s == sender then
      return s,m
    end
  end
end

local function GetRednet(sender,message)

  if functions[message] ~= nil then
    rednet.send(sender,functions[message])
    local DoWhat = message
    local sender,message = getMessage(sender)
    if DoWhat == "CheckPass" then
      print(sender)
      print(textutils.serialise(message))
      rednet.send(sender,checkPass(message["Username"],message["Password"]))
    elseif DoWhat == "NewUser" then
      print(textutils.serialise(message))
      if CheckPass(message["Existing user username"],message["Existing user password"]) then
        StoreData.Edit("/Users",message["New user username"],message["New user password"])
        print(textutils.serialise(StoreData.Load("/Users")))
        rednet.send(sender,true)
      end
    end
   else
     rednet.send(sender,false)
   end
  sleep(0)
end

local args = {...}
local sender = args[1]
local message = args[2]
GetRednet(sender,message)