Controversial idea: An ephemeral blockchain - a chain that keeps the latest state and forgets tx older than a certain amount of time (ideally in a way where there could be plausible deniability of past transactions)

This solves having data on the chain forever.

Working to decentralize the web

Leading the Protocol Design and Cryptography team at Protocol Labs

How? Make consensus and tx keys public after a consensus checkpoint

(1) users and consensus nodes have a master key and one derived epoch key 
(2) post your encrypted key with a timelock decryption (e.g. via drand)
(3) when the epoch ends, a checkpoint is made with the new key and the previous keys are revealed

Why is this important?

GDPR compliant chains/right to be forgotten chains: no need to remember the full past - ok to post things on-chain that we want to delete in the future