All they need is a working computer with electricity and internet connection - in the middle of nowhere. | Far from impossible but not very probable.
You are aware that there are more cellphones than flush toilets in the world?
I am aware it's really hard to find any kind of artificial toilets -in the middle of nowhere-, let alone one with a working water flush feature.
It's not that easy with cellphones:
- confirming an incoming transaction but not being able to spend the coins doesn't really cut it (it's kind of a leverage trade at that point)
- online wallets like blockchain.info are not real Bitcoin wallets, these are third-party services (you need to trust in the operator = not trustless like a true blockchain crunching wallet)
Are there fully working Bitcoin wallets for Android, iOS and Windows Phone (true trustless wallet with sending capabilities)?
