password to become user group

// https://i.imgur.com/UN0Pcbv.png
// https://forum.facepunch.com/f/gmoddev/btrsh/I-want-to-make-command-so-that-the-user-has-to-enter-a-password-to-become-admin/

if CLIENT then return end

local Passwords = {
    ['admin'] = "YWRtaW4=",
    ['superadmin'] = "c3VwZXJhZG1pbg==",
    ['user'] = "dXNlcg==",
}

local Player = FindMetaTable("Player")

function becomeAdmin(ply, pass)
    if !pass then return end

    for k, v in pairs(Passwords) do
        if pass == v then
            ply:SetNWString("UserGroup", k)
            ply:ChatPrint("Your usergroup was changed to '" ..  k .. "'.")
        end
    end
end

hook.Add("PlayerSay", "_PlayerSay", function(ply, txt, tm)
    local cmd, args, str

    str = txt

    if string.Left(txt, 1) == "!" then
        txt = txt:gsub( "^.(%S+)", function( match )
            cmd = match
            return ""
        end, 1)
    end

    args = string.Explode(" ", txt)
    table.remove(args, 1)

    if cmd == "password" then
        becomeAdmin(ply, args[1])

        return ""
    end
end)