Redactable Blockchain, or Rewriting History in Bitcoin and Friends [pdf] (eprint.iacr.org)

> Redactions can be made only by authorized entities and under specific constraints ...

This makes the network essentially centralized. Why not just use a db that is cheaper?

> there are several reasons to prefer an editable blockchain, spanning from the necessity to remove inappropriate content

There are already blockchains that do not allow for embedding of arbitrary data, because it's all elliptic curve points and Schnorr signatures.