> One can imagine some combination of the primitives in which you could prove that you added here the same amount you subtracted from there, that neither total

> One can imagine some combination of the primitives in which you could prove that you added here the same amount you subtracted from there, that neither total is below zero, but for which the number actually transferred is encrypted You are exactly describing Mimblewimble. https://github.com/ignopeverell/grin/blob/master/doc/intro.md https://github.com/ignopeverell/grin/blob/master/doc/intro.m...