One of the largest cryptocurrency thefts took place in August 2021. Digital currency valued at $613 million was stolen by hackers from Poly Network. They took advantage of a flaw in Poly Network’s digital contract. They further compromised the security of the company’s smart contracts by taking advantage of this security flaw. The disclosure of their client data and ultimately revenue loss were the results of this. This article will cover how to ensure the security during smart contract development, its correct application, and the most frequently encountered flaws in a smart contracts platform to avoid such circumstances.