Abstract
Smart contracts are simply self-activated contracts between two parties. The idea behind their implementation relies on the concept of blockchain, wherein the details and execution of the contract are turned into code and distributed among users of a network. This process controls counterfeiting and money laundering by its ability to trace who owes whom. It also boosts the general economy. This research paper shows how smart contracts in modern-day systems have changed the approach to money tracing. We present case studies about the uses of smart contracts with high levels of security and privacy. As a building block of smart contracts, a brief description of blockchain is provided in an introduction. Among other cryptography methods and techniques, the usage of hashing and hash functions in blockchain security are also explained. We also explore the real-time applications of blockchain and smart contract techniques in real estate. The main advantage of this research paper is that it discusses a state-of-the-art subject, as most of the articles referenced in this paper are from 2018 and onward.