I've seen some recent research proposals: https://www.computer.org/csdl/proceedings/sp/2019/6660/00/666000a629-abs.html https://www.computer.org/csdl/proceeding

I've seen some recent research proposals: https://www.computer.org/csdl/proceedings/sp/2019/6660/00/666000a629-abs.html https://www.computer.org/csdl/proceedings/sp/2019/6660/00/66... The basic idea is you have a way to delete the data associated with an old transaction but not the transaction itself. A majority have to agree to the redaction though and the fact something has been redacted is recorded.