My only concern about this is the lock-in. Has that been considered? What happens when I decide to stop using TextSecure? Will I need to tell everyone to delete a key from their phone or something, so messages don't come through garbled? Will they not come through at all, because they'll attempt to use the data channel and my phone wont bother even attempting to pick them up anymore?
What if I lose my phone and get my provider to send me a replacement? I guess I wont be able to read the incoming texts anymore? If some auto-negotiation takes place to change my key, then isn't that exposing a trivial MITM? Would I be alerted of such a key change?
I had this happen to me - where someone I was messaging stopped using it without telling me. One message came through as garbled, but then there's an easy way to "end secure session" and new messages go through in plaintext. For switching between textsecure phones, I just re-initiated a key exchange. This was months ago, so it may have changed
What if I lose my phone and get my provider to send me a replacement? I guess I wont be able to read the incoming texts anymore? If some auto-negotiation takes place to change my key, then isn't that exposing a trivial MITM? Would I be alerted of such a key change?