[brrrrrm]

amazingly, the browser has pretty much solved all of this. fully compatible EMCAscript implementations on every single device with hardware access (such as the camera, as is needed in this post)

I don't buy your "security through difficulty" argument for that reason alone.

[danpalmer]

I don't really mean "security through difficulty", I mean that on phones we have sandboxing, permissions, and a bunch of other factors that make phones much more secure than the average desktop/laptop. Browsers do provide a pretty good option here, but that comes at the cost of the browsers themselves being highly complex, and privileged software on the devices.

OP writing this prototype as a web app would likely have been the path of least resistance to having something work on mobile.