The thing is, for the Horcrux to have any effect at all you need at least three devices per endpoint. And at that point using split TCB architecture is much bet

The thing is, for the Horcrux to have any effect at all you need at least three devices per endpoint. And at that point using split TCB architecture is much better as under some assumptions it's provably secure against remote key exfiltration. See my work on TFC here: https://github.com/maqp/tfc https://github.com/maqp/tfc