Signal and WhatsApp require a smartphone though, so not fully cross platform, and tied to their (closed) client software. Not sure if Telegram requires a smartphone too, but it does seem to require a phone number at least.
I had signed up for Telegram on a phone, so can't say whether you can sign up w/o a phone (I think it would require SMS verification).
It doesn't need you to be logged in on any phone however. You can use just the desktop app. In fact I am on some really crowded and hyperactive Telegram groups so can't even imagine keeping it on my phone. Besides not a single one of my IRL friends use Telegram. I see 3-4 names, maybe they had signed up once.
It is for Whatsapp. Not only for sign-up, but actually all communication on the web version goes through the app running on your phone. The web "session" times out constantly, so I'd have to re-pair it with my phone all the time. If I still decided to use whatsapp.
To be really pedantic; a smartphone is not required for WhatsApp. You can activate a Google voice number with a landline, then use your Google voice number to activate WhatsApp running in BlueStacks or your emulator of choice.
Source: I did this for a few months. I'm not quite sure why...
Your phone connects to WhatsApp's servers. So does your laptop. The bridging is likely done server-side. I assume this is done because WhatsApp is (probably) using end-to-end encryption, so everything must be ran by your phone (which is the only place where your private key is stored) in order to encrypt the messages.
The problem is that you need to own that same phone number permanently. Phone numbers are tied to exactly one SIM card, which is tied to exactly one telco in one country. Too many ties.
Threema doesn't require a phone number but it's not free.
Depends on a country, in Sweden you can move your mobile number to any telco, and anyone can look up your number and your home address using something like [0]. But yes, it is still tied to a country.
But I still need to keep the SIM card active or I could never switch phones (or reinstall the phone OS) without losing my Signal identity.
I cannot ever let go of the phone number I used to activate Signal. In practice, that means I need to keep paying for a phone tariff I may no longer want.
True. I was assuming most people have at least one phone number they want to keep long term (even if it's not always active with their cell). Note though that signal will also work fine with non-traditional services that provide free or much cheaper phone numbers like google voice (US), skype, or twilio.
It is true though that you do need to maintain a phone number. That is one of the trade-offs they made to allow it to actually be usable. I have not seen a better solution for encrypted communication yet.
Threema appears to optionally do the exact same thing. Signal eschews the flexibility to ensure more universal usability by being able to assume that anyone who uses signal can be associated with their phone number. An assumption that holds for the vast vast majority of potential users.
I don't see how making phone numbers mandatory makes Signal easier to use at all. There must be another reason for this restriction. Some say it's for spam protection.
Signal will work with Google Voice, but as far as I can tell you still need a smartphone to use it. Without that, you can't even set up an account because you need to scan an OCR code first.
I was talking about Signal. Sorry I didn't make that clear. The phone number is your identity. Changing it means reregistering with a different number.
[Edit] And I think it's essentially the same with WhatsApp, only they now make it a less manual process.
Incorrect. Whatsapp refuses to open on my iPad and isn't even available in the App Store. The only reason it got on there was a glitch in Apple's app sync which must've auto-downloaded it since I have it on my iPhone.
You do need one to set it up, right? I had to scan a QR code displayed on my desktop with my phone. (I could continue to use the desktop app while my phone was being repaired, though, which was great.)
You're using signal in a browser on your linux desktop.
Poke me when there's any way to connect via bitlbee or libpurple, like there is for ICQ, jabber, etc.
