Simple Encoding

--After I looked this up on December 27th 2014, I found out this is basically (exactly) a hex Vigenere Ciphet
local nify = { "0", "1","2","3","4","5","6","7","8","9","a","b","c","d","e","f" }

local function code(key, msg, mode)
 key = tostring(key)
 msg = tostring(msg)
 local kn = 1
 local nmsg = ""
 for i = 1, #msg do
  cc = string.sub(msg, i, i)
  for b = 1, 16 do
   if cc == nify[b] then
    ccn = b
   end
  end
  for c = 1, 16 do
   if string.sub(key, kn, kn) == nify[c] then
    knn = c
   end
  end
  if mode == "encode" then
   ccn = ccn + knn
  elseif mode == "decode" then
   ccn = ccn - knn
  end
  if ccn >= 17 then
   ccn = ccn - 16
  end
  if ccn <= 0 then
   ccn = ccn + 16
  end
  --print(ccn)
  nmsg = nmsg..nify[ccn]
  if kn == #key then
   kn = 1
  else
   kn = kn +1
  end
 end
 return nmsg
end

function decode(key, msg)
 local tr = code(key, msg, "decode")
 return tr
end

function encode(key, msg)
 local tr = code(key, msg, "encode")
 return tr
end