String variable character encoding

Hi!

I need to store data which is really just a very long string of one-byte numbers. The “official” way would be to store it as a table, but to save memory (and data transfer), I would llike to really have a data format which is just this - a numer of one byte values. As much as I know (please correct me), only the string variable fits this description. But I don’t know how characters are encoded in the Lua / Roblox string variable. If it is just an ASCII derivate like Latin-1, it would work. But I fear, that Roblox “translates” strings to different encodings. It would be the same “string” of letters, after all. But as I just need the numerical values, this would ruin my data.
I can’t find this information on the reference pages.
Thanks