Is there a way to provably destroy a piece of information? The closest thing I heard of was the Z-Cash "ceremony" [1]. If there was, we could create messages that are provably and absolutely timestamped.
Another possible way would be crafting the message in a way that requires a low-entropy system, like a living human person, a sophisticated computer, or an immense power source. But, this would only be useful on extreme time scales, or within limited space.
Another possible way would be crafting the message in a way that requires a low-entropy system, like a living human person, a sophisticated computer, or an immense power source. But, this would only be useful on extreme time scales, or within limited space.
[1]: https://z.cash/technology/paramgen/