Key type concept

--done in luau
local msg = 'wow potato'

function GenerateRandomKey(len)local res=''for _=1,len do res..=tostring(math.random(1,10)-1)end return res end

function FACT_OffsetLetter(mult)
    return function(msg,key)
        local res=''

        for i=1,#msg do
            local let = msg:sub(i,i)
            local offset = key:sub(i,i)

            local NewByte =
                (let:byte() - 32 + offset * mult) % 223

            local newlet = string.char(NewByte + 32)
            res ..= newlet
        end

        return res
    end
end

local Encrypt = FACT_OffsetLetter(1)
local Decrypt = FACT_OffsetLetter(-1)

local key = GenerateRandomKey(#msg)
print(msg,key)

local m2 = Encrypt(msg,key)

print(m2)

local m3 = Decrypt(m2,key)

print(m3)