This appears to be virtually contradiction in terms. In IT security racket we have always stressed the importance of having physical control of the hardware. Anyone with physical access to the device could gain root access to the system and from then on do pretty much anything that wanted.
By extension we could only trust the application, and the safety of our data contained in it, if we also trusted the physical safety of hardware.
The Microsoft verdict is interesting in this regard. If the cloud vendor is US company, a US company own the hardware and it is thus subject to US jurisdiction regardless of there it is located. At the moment we do not know if this verdict will survive a supreme court appeal. But in any eventuality the conundrum remains: Can we have trusted computing on a untrusted computing platform ?

I’m going to try to demonstrate that this is possible for a server application.

Clearly a cloud based web application constructed to work on an untrusted platform would be very different in it’s internal workings from how things are generally done now.
The working model that I propose to pursue will be a web service with thick clients. The web service will run on a cloud vendor subject to US jurisdiction, AWS. I will demonstrate that the sensitive application data will sit on the AWS in encrypted form, at no time be decrypted on the AWS nor have the encryption keys at any point be on the AWS in clear.
The thick client will be an Android app.

In the event that I am successful using a thick client (app), I will attempt the same using a thin client (web browser).