"One of the biggest issues in IoT is knowing who you are connecting to. That requirement for trust mechanisms across millions or billions of sensors is what makes a distributed system like a blockchain vital," said Richard Mark Soley, Ph.D., executive director of the Industrial Internet Consortium, based in Needham, Mass. But marrying contracts and IoT -- "smart contracts" -- may be a different matter. Where blockchain distributes a ledger system, the "contract" concept extends the function of the ledger to include a language for terms of agreement and measurements to determine if certain conditions have been met. "A smart contract can be designed to execute automatically when both the buyer and the seller conditions are met," said Bill Fearnley Jr., a research director of worldwide compliance, fraud and risk analytics strategies and blockchain at IDC.