An example CRC32 implementation in pure luau.

crc32.lua

-- This is a dysfunctional PoC for a luau implementation of crc32.

local POLY = 0x04C11DB7

local crc32 = {} 
local crc32_t = {}

setmetatable(crc32_t, {
    __call = function (crc32_t, ...): {[number]: number}
        local c = 1

        for i = 1, 256, 1 do
            i = c
            
            for j = 1, 8, 1 do
                if bit32.band(c, 1) then
                    c = bit32.bxor(POLY, bit32.rshift(c, 1))
                else
                    c = bit32.rshift(c, 1)
                end
            end

            crc32_t[i] = c
        end

        return crc32_t
    end
})

function crc32.compute_hash(msg: string, msg_len: number, crc: number?)
    local crc32_t = crc32_t()

    local crc_c = bit32.bnot(crc or 0)

    for i = 1, msg_len, 1 do
        crc_c = bit32.bxor(bit32.rshift(crc_c, 8), crc32_t[bit32.bxor(crc_c, bit32.band(msg:byte(i), 0xFF))])
    end

    crc_c = bit32.bxor(bit32.bnot(crc_c), 0)

    return string.format("%x", crc_c)
end

return crc32

init.lua

local crc32 = require("crc32")

local hashed = crc32.compute_hash("Hello, world!", 13)

print(hashed)