[dTal]

Also note that as it stands encrypted SMS is technically superior. This is Moxie's comment on GCM-free Signal:

> I expect it to have high battery consumption and an unreliable user experience, but would be fine with it if it comes with a warning and only runs in the absence of play services

You don't get high battery consumption, or unreliable user experience, or a requirement for Play Services with pure SMS encryption.

SMS encryption is actually quite a tricksy problem. TextSecure's entire purpose (over bog standard IM OTR) was to solve it, providing individual message-level forward secrecy. This is why it's so perplexing to me that they dropped it (I understand that part of the reason is that iOS simply does not allow it)

https://whispersystems.org/blog/advanced-ratcheting/