Exactly how is ZEN CHAT going to work on a phone anyway?  I understand they will have an app maybe for your phone.  Tell me exactly how that's going to keep the NSA, Apple, Samsung, etc... away from still seeing every single keystroke you make?  The ONLY way to keep key strokes encrypted is to stroke keys on an external hardware device; like Trezor for example.  Your key strokes can easily be seen on a desktop, laptop and mobile phone by other means before it's sent through an app to be encrypted and go on the blockchain.

The ONLY way ZEN is going to pull this off is to create an external hardware device.  

Is someone going to honestly carry around an external hardware device to connect to their mobile phone via bluetooth to chat to someone by typing on that external hardware device?  Good luck getting people to do that.

If people want their data PRIVATE, they would need to keep it on a different external device that encrypts the data before the data actually goes through another device and ride on the internet.  No?

So, once again, for ZEN to actually pull this off, they will need to create an external hardware device.  Preferably a device that doubles as an unlocked mobile phone with the ability to work on any carrier and connect to the ZEN blockchain via a data link.  Why preferably a mobile phone?  Because most people will not want to carry around multiple pieces of hardware for the sake of privacy.  Most don't even care about their privacy at the expense of convenience.  

The downside to creating an encrypted mobile device to keep ALL your data PRIVATE is people should not download other apps to that device that could potentially spy on them or take their coins.  They won't be able to play games on their encrypted mobile phone if their into that kind of thing.  Again, ZEN is forced to wrestle with solving the issue of "inconvenience" using such a device for the sake of privacy.  I would if someone made it available.  My major concern in that case would be, "Is this another Cook telling us our data is protected, when in reality it's not?  In the end, the user would have to TRUST the word of the manufacturer and/or provider that there really is no way for ANYONE to have a key to the encryption to actually see our data, etc...

If I'm wrong, please correct me...