It is quite easy - to tell...not to make ;-)


You need to make it as easy as dropbox... but better

easy handling with all the advantages of crypto

... for me thats sounds like an incredible amount of work- but for the average user is usability the key.
look at whatsapp- nearly everybody is using it despite all the problems around and despite there are much better solutions on the market... but it is easy

I really like your attitude- asking around what people really want
Good luck!