Smart Communities seeks to thrive in a context of broadband economy, its engine and reason for being. The success of any community is a function of its economic backbone or the supply chain. A supply chain can be defined as the integration of customers, retailers, distributors and manufacturers. The changing technology has made the survival in commerce highly competitive and price sensitive. Blockchain technology can be the game-changer for decentralizing infrastructure and building a trust layer for business logic. BlockCom is a commerce model based on the emerging technology of blockchain. This paper presents a double auction scheme for energy trading between customers and suppliers. A smart contract implements a distributed algorithm to maximize individual participating profit. Parties bid to smart contract which act as auctioneer for maximizing the profit. Mathematical parameter named credibility score has been created to deal with trust issues in the decentralized network using byzantine fault tolerant mechanism. BlockCom provides a fresh perspective on the concept of supply chain and commerce.