Gupta was an immediate descendant of Brahmi, used in Northern India from about 400-800 AD, and the forerunner of many important scripts of Northern India and the Himalaya.
The Gupta empire was very powerful and important. “Gupta” is still a common name in India today.
Surviving examples of the script are mostly on stone and iron pillars, and on gold coins. If you want to leave a message for the future, stamping it on coins is probably a good way to do it. (I am a little concerned that future archeologists will think that Canadians worshiped loons, beavers, and moose, and that Americans spoke Latin.)