Perhaps remarkably, the US intelligence community is funding work on this problem in the open, as part of IARPA HIATUS [1]. The program's initial phase is wind

Perhaps remarkably, the US intelligence community is funding work on this problem in the open, as part of IARPA HIATUS [1]. The program's initial phase is winding down now, so some of the performers' papers ought to be hitting the ArXiV before too many more months. [1] https://www.iarpa.gov/research-programs/hiatus https://www.iarpa.gov/research-programs/hiatus