Lua 5.1+ base64 v3.0 (c) 2009 by Alex Kloss <alexthkloss@web.de> Licensed under the terms of the LGPL2

base64.lua

local function base64(data)
    -- Lua 5.1+ base64 v3.0 (c) 2009 by Alex Kloss <alexthkloss@web.de>
    -- Licensed under the terms of the LGPL2
    local b = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'

    return ((data:gsub('.', function(x)
        local r, b = '', x:byte()
        for i = 8, 1, -1 do r = r .. (b % 2 ^ i - b % 2 ^ (i - 1) > 0 and '1' or '0') end
        return r;
    end) .. '0000'):gsub('%d%d%d?%d?%d?%d?', function(x)
        if (#x < 6) then return '' end
        local c = 0
        for i = 1, 6 do c = c + (x:sub(i, i) == '1' and 2 ^ (6 - i) or 0) end
        return b:sub(c + 1, c + 1)
    end) .. ({ '', '==', '=' })[#data % 3 + 1])
end