Thanks for the link. I think I saw his talk about the topic and that milagro resonates well with it. The use of threshold encryption works around an unfortunate aspect of IBE and is practical today.

PS: As I grow older, I become more accepting of the fact that state power is not going anywhere soon. If multiple authorities (preferably under different jurisdictions) can be coerced into deriving client secrets for law enforcement with proper oversight, like public visibilty of the amount intervention and auditabilty by data protection officers, that would be acceptable to me and better than outlawing homebrewed encryption or more drastic backdooring measures.