mainphone

require("/stringtools")()
local modem = peripheral.find("modem")
local channel = 49549
local response_channel = 48548
local all_chars = {}
local id = os.getComputerID()

for i = 0, 255 do
    all_chars[i + 1] = string.char(i)
end

modem.open(response_channel)

local function encrypt(message)
    message = string.fracture(message)
    local new = ""
    for _, char in pairs(message) do
        for _idx, _char in ipairs(all_chars) do
            if char == _char then
                new = new..all_chars[(_idx+id)%#all_chars]
            end
        end
    end
    return new.."_"..id
end

local function decrypt(message)
    message = string.fracture(message)
    local unlock_id = ""
    for i = #message, 1, -1 do
        if message[i] ~= "_" then
            unlock_id = unlock_id..message[i]
        else
            for j = i, #message do
                message[j] = nil
            end
            break
        end
    end
    unlock_id = tonumber(string.reverse(unlock_id))
    local new = ""
    for _, char in pairs(message) do
        for _idx, _char in ipairs(all_chars) do
            if char == _char then
                new = new..all_chars[(_idx-unlock_id)%#all_chars]
            end
        end
    end
    return new
end

repeat
    local _, _, _, _, message, _ = os.pullEvent("modem_message")
    print(message)


until false