Computercraft Keycard Reader System V1 [Part 1 - Reader]

--[[ Info

Save this program as: "startup". The advanced computer this will be used on should be dedicated for this program only.

This program is part of a two part keycard reading system. Instead of using a password stored on the floppy disk,
the program uses the unique ID of each floppy disk. Since the computer running this program will be hooked up to a more exposed
disk drive, it is not recommended to have this system hooked up to a door lock, disk drive server, or anything important due to
the higher risk of the computer being hijacked (as the startup program on a floppy disk overrides the computer's startup).

Note: The reader is designed to work with my validator, however you can use your own program if you know the way it communicates.
]]--
 -- Set this to the drive the system will use to read the keycard
side = "bottom"

-- Ejects disks on startup to unclog itself
disk.eject(side)
-- Prevents program termination (to prevent easy tampering)
os.pullEvent = os.pullEventRaw
term.clear()
term.setCursorPos(1,1)
term.setTextColor(colors.blue)
-- Change brackets to the name of the area the reader is located (e.g. Example Town, Lobby, Workshop, etc.)
print("Welcome to <Area Name Here>")
print("Please make sure validator is activated!")
print("Insert Keycard Now")
-- Security Variable (Don't touch this)
tk = 1
-- Opens Rednet communications
rednet.open("left")
-- Main Program
while true do
    -- Waits for a disk to be inserted before continuing
    event,side = os.pullEvent("disk")
    -- Security code - Quarantines and deletes startup programs on disks
    if fs.exists("disk/startup") then
        term.setTextColor(colors.red)
        print("WARNING: Hijacking attempt detected!")
        c = 0
        while tk == 1 do
            -- If a program called startup_#### doesn't exist then:
            if not fs.exists("startup_" .. c) then
                -- resets security variable
                tk = 0
                -- stores a copy of the startup program to the computer as "startup_####"
                shell.run("copy disk/startup", "startup_" .. c)
            else
                -- Increases the number by 1
                sleep(0.1)
                c = c + 1
            end
        -- Deletes the startup program on the floppy disk
        shell.run("delete disk/startup")
        print("Program logged and deleted!")
        sleep(3)
        -- Ejects disk then reboots the computer
        disk.eject(side)
        os.reboot()
        end
    end
    -- Checks if a data disk was inserted or if a random object was inserted instead
    if not disk.hasData(side) then
        term.setTextColor(colors.red)
        print("Warning: Invalid Object Detected!")
        sleep(3)
        disk.eject(side)
        os.reboot()
    end
    -- Program Communications
    -- Grabs disk's unique ID
    IDdata = disk.getID(side)
    term.setTextColor(colors.cyan)
    print("Transmitting Data...")
    print("Do not restart the system")
    print("ID #: " ..IDdata)
    sleep(2)
    rednet.broadcast(IDdata)
    print("Awaiting Response..")
    -- Waits 5 seconds for a response
    id,resp1 = rednet.receive(5)
    -- Checks response from validator
    if resp1 == "Break" then
    -- If the ID was a maintenance card (Exits to terminal)
        term.setTextColor(colors.orange)
        term.setCursorPos(1,7)
        print("Maintenance Card Detected!")
        print("Welcome Operator!")
        disk.eject(side)
        break;
    elseif resp1 == "Denied" then
    -- If the ID was rejected
        term.setTextColor(colors.red)
        sleep(2)
        term.setCursorPos(1,7)
        print("Access Denied!        ")
        sleep(2)
        disk.eject(side)
        os.reboot()
    elseif resp1 == "Granted" then
    -- If the ID was accepted
        sleep(1)
        rednet.broadcast("resume")
        term.setCursorPos(1,7)
        print("Response Recieved      ")
    else
    -- Timed out or invalid response
        term.setTextColor(colors.red)
        sleep(1)
        term.setCursorPos(1,7)
        print("Error: Invalid Response/Timed Out")
        print("Please try again later")
        sleep(3)
        disk.eject(side)
        os.reboot()
    end
    id,name = rednet.receive()
    term.setTextColor(colors.green)
    print("Access Granted! Welcome " ..name.. "!")
    sleep(2)
    disk.eject(side)
    os.reboot()
end