This isn't making a whole lot of sense to me. Capabilities seem to be about making sure that sandboxed software doesn't get unauthorized access; it presumes you have a trusted environment (whether software, OS, or hardware) to enforce the capabilities.

Meanwhile, blockchain computation is about getting useful work out of untrusted participants. It doesn't seem like a fit.

Also, how do you do any calculation at all without decrypting the data? Or if you're thinking homomorphic encyption, what does a blockchain have to do with it?