Block-chain, at least as far as bit coin is concerned, consumes massive amounts of power $$$$$$$ and service Capex hardware. Not sure how that overlaps with IBM's cloud use of Block-chain, cost wise, but lets assume it is also a hardware and power hog maintaining that block chain based cloud date/security?
I presume, that the energy efficient Q-Dots do not/will not have the power handicap?
But the emission pattern of a Q-Dot physical key would need to be stored as a block-chain pattern online in the cloud, for the cloud to recognize a scanned Q-Dot physical key as the real McCoy?
Would this be the next low cost chip on a plastic credit and debit card?
And on Rx drugs as Kurt has mentioned....
Keys to start cars? Key to unlock buildings.....etc