Smart Contract enabled Online Examination System Based in Blockchain Network

In today's world, data is one of the most important assets than any other. Every user wants to secure their data from the outer world. Blockchain is the prominent technology that can provide the security and loyalty of data. Initially, blockchain has been used for the cryptocurrency and all the data were available on the public distributed ledger. But now a days, private blockchain is widely used within the organizations for data security. Blockchain engenders decentralized systems in which data can be send and receive securely and efficiently over the network. It means there is everything is hidden from the outer world; only authorized users have the authority to read and write the data on the network. World's topmost industries; like Walmart, IBM, Google, etc. are adopting the blockchain technology to build the Decentralized Applications (DApps). Decentralized Applications are the smart systems that are executed on a distributed computer network. Blockchain enables one of the most secure applications called Smart Contract. Smart Contracts are the computerized and secured distributed ledgers that enable secure, transparent, and tamper-proof transactions. Smart contracts create and verify the data with the help of hashing. It is a mathematical procedure that uses the most powerful algorithm cryptographic Hash Algorithm i.e. SHA-256. It engenders 256-bit signature for the input text. Ethereum Blockchain Platform is a widely used platform to build the DApps. This platform is a public network platform, which is open to all and anyone can participate in this network to send and receives the transactions. Blockchain Technology is enabled in every sector like marketing, business, education and supply-chain, etc. This paper carries out the study Ethereum Blockchain Platform in Education System. We have developed an application for the Online-Examination System using Blockchain Ethereum Platform with features of Smart Contracts that enables server runtime environment NodeJS and MongoDB database system. Blockchain-based system is truly more secure than all the Cloud-based systems. We have also analysed that how blockchain based online examination is more trustworthy as compare the other systems.