Encryption Test

function encrypt(txt, key)
  enc = ""
  len = string.len(txt, key)

  for i = 1,len do
    char = string.sub(txt, i, i)
    byte = string.byte(char)
    byte2 = byte+key
    char2 = string.char(byte2)
    enc = enc..char2
  end
end

function decrypt(txt, key)
  dec = ""
  len = string.len(txt)

  for i = 1,len do
    char = string.sub(txt, i, i)
    byte = string.byte(char)
    byte2 = byte-key
    char2 = string.char(byte2)
    dec = dec..char2
  end
end