Lua encryption algorythm - encryption

Question

So I am working on a encryption algorythm in lua called S22. I have got the encryption part working but the decryption is a lot harder. Any ideas?
My encryption algorythm:
function S22Encrypt(MSG, bit)
local resources = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}
local finalstring = ""
local count = 0
MSG:gsub(".", function(c)
for i,v in pairs(resources) do
count = count + 1
if v == c then
finalstring = finalstring .. count * bit /69
count = 0
end
end
end)
return finalstring
end
My attempt at decryption:
function S22Decrypt(MSG, bit)
local resources = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}
local finalstring = ""
local count = 0
MSG:gsub(".", function(c)
for i,v in pairs(resources) do
count = count + 1
if v == c then
local nmr = count / bit *69
local count2 = 0
for a,b in pairs(resources) do
count2 = count2 + 1
if count2 == nmr then
finalstring = finalstring .. count2 / bit * 69
end
end
count = 0
end
end
end)
return finalstring
end

Answer 1

Decrypting is done by trying every possible value of count and comparing the corresponding code:
function S22Decrypt(MSG, bit)
local resources = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}
local finalstring = ""
local count = 0
local resource_idx = 0
while MSG ~= "" do
count = count + 1
if count > 1000 then
return nil, "Can not decrypt"
end
resource_idx = resource_idx + 1
if resource_idx > #resources then
resource_idx = resource_idx - #resources
finalstring = finalstring .. " "
end
local code = "" .. count * bit /69
if MSG:sub(1, #code) == code then
MSG = MSG:sub(#code + 1)
finalstring = finalstring .. resources[resource_idx]
count = #resources - resource_idx
resource_idx = 0
end
end
return finalstring
end
Please note that if you are encrypting on one system and decrypting on another then Lua version of encrypting script and Lua version of decrypting script must be either both Lua 5.3+ or both Lua 5.2-
For example, the word "hello" encrypted on Lua 5.1 will not be decryptable on Lua 5.4 (and vice versa) due to integer-to-string differences (42 vs 42.0)