Smart Contracts Resilient against Malicious Attacks in Permission-less Blockchain

The applications of Blockchain are rapidly growing across all the sectors and blockchain has become a one- stop solution to achieve data integrity. For both small and large businesses, blockchain can be used to enhance security, privacy, and data openness. A block gets added in the blockchain after reaching an agreement among the peers using a consensus algorithm. In a permission-less blockchain, the peers can behave maliciously. A consensus algorithm should prohibit malicious nodes/peers from adding invalid blocks to the blockchain, controlling the network while also granting equal rights to all nodes and mandating their participation in the consensus process. Smart contracts are the programs stored in a blockchain that run when specific conditions are met. There are certain attacks on blockchain smart contracts — Reentrancy attacks, Arithmetic overflow/underflow attack, Short address attack, Denial of service etc. The root cause of such attacks on smart contracts are the vulnerabilities existing in the smart contracts. This paper aims at correcting the vulnerabilities in the smart contracts thus eliminating such malicious attacks in the permission-less blockchains.