Alternatives to PGP should probably include S/MIME and Signify, depending on what you want to do with it.
Soft disagree with that. Signal text and voice chat works just fine if all of your communicating party's machines are offline. (Well, I mean, obviously your voice call won't be answered, but otherwise...)
2. it absolutely doesn't require a smartphone, just a routable phone number, that can be a cell phone, a landline, a voip number or a google voice number: http://support.whispersystems.org/hc/en-us/articles/21247611...
I never said otherwise. What I said was:
> Signal text and voice chat works just fine if all of your communicating party's machines are offline.
This was in response to an assertion that Signal was designed for the "always-online" world. Signal works just fine when your contact is completely offline for extended periods of time.