IoT is one of the most popular and ubiquitous technology in this decade .IoT is everywhere now. Cryptoeconomics is an area of applied cryptography and it is not a subfield of economics rather it is technology of economic incentives and economic theory into elucidation. Bitcoin, ethereum are some of the example for block chains and are yields of cryptoeconomics. Another name for blockchain technology is a Distributed Ledger Technology that will influence the aspects of digital business .Combining blockchain technology and IoT results in increasing economic growth of the business environment. Merging of the above two technology and security issues are the focus of this paper .In concern with the security of the block chain technology 15% of the attack is handled by SHA algorithms. Public- private key algorithms are proposed to protect block chain architecture. To improved security in block chain set of mechanism will be focused in this paper for decentralized prediction market, auction system, block chain computation and storage.