It&#x27;s harder to deploy updatable encryption on a federated protocol than a centralized one, but as I see it, the difficulties are social rather than technical. Deploying updatable, usable encryption on P2P is technically more difficult than on federation or centralization, but I&#x27;m not convinced it&#x27;s socially more difficult.<p>The core problem of updating federated systems is that big players can choose not to play. If Google or Yahoo decide not to support a change to email, the change is dead in the water. This isn&#x27;t just hard, it&#x27;s intractable.<p>But with P2P systems, non-reliance on peers doing anything in particular is built-in. For example, peers that don&#x27;t support a change limit the size of the swarm you can peer with, but they don&#x27;t inherently break the feature as long as there are some peers who support the change. Many Bittorrent clients support encryption and many don&#x27;t, many bitcoin miners support alternate protocols to speed up pooled mining, and many don&#x27;t.<p>I don&#x27;t know what the implications of this would be for a system like Signal. It maybe that it doesn&#x27;t solve anything; I&#x27;m just not ready to conclude that for myself yet and I&#x27;d be interested to hear Moxie&#x27;s take.