So today I got Authy, (because I wanted 2FA on my google account).
Anyway, it works grand, and I scanned the google QR code and all works well.
One thing is weird though, I have coinbase on my iPhone as I buy bitcoins sometimes. When I launched the Authy app it immediately offered Coinbase codes as well as google codes.
The thing is I didn't use google 2FA for Coinbase, my coinbase account is totally separate from google.
So, minus the fact that I had the coinbase app on my iPhone (and iPhone apps are supposed to be completely sandboxed and don't communicate), how did Authy know I had a coinbase account?
Bonus question, which is the weirdest thing ever, when I went to sign into Coinbase (after having downloaded the authy app), rather than sending me an SMS to my phone, Coinbase ASKED for the Authy code...
Also the Authy app sent me a push notification on my phone to suggest I open it to get my code. How is this POSSIBLE?
I didn't link Authy and coinbase, the ONLY link is my coinbase user name is my google email address... please help explain.