AbstractThis paper is about the Introduction In today’s world, which we can call it as a centralized world as it consists of more of centralised social structures unlike the world that use to be before the age of agriculture began, where people use to live in small groups knowing each and every one in the group which allows them to avoid committing any kind of bad actions, which we can call it as a decentralised social structure. Taking the centralised society in to context, in this society there are large number of centralised groups where people are rarely aware of the other people in their group as well as other groups. In this scenario, if someone wants to have a transaction or a communication or may be any kind of deal, they have to face a major question about how to trust the other person to have a communication or a transaction or any kind of a deal. There exists some of the processes, with which people can go through and can judge whether they can trust the other person or not, but these are not 100% reliable and very slow process. These processes include agreements, the agreement is a set of terms on which the two persons agree to follow while they are doing a transaction or implementing any kind of deal. There are numerous kinds of agreements which are dealt by a third person or can be called as a third party or an a mediator other than these two persons in between whom the agreement will be made. The so called agreements or contracts were used in business, personal relationships like marriages, politics., what not almost everywhere in every kind of relationship. As the world is changing tremendously with rapid growth, the usual contracts which are made on paper or soft copies with the third parties seems to be a slower process as a result a new contracts specifically named as Smart contracts were came in to tremendous use in recent years. The word Smart Contracts was first introduced in 1994 by the computer scientist named Nick Szabo. This is going to be furtherly explained under the heading Smart contracts. These smart contracts can be done using the technology called Blockchain and the most specifically designed platform for the use of smart contracts is Ethereum. A clear explanation of Blockchain and Ethereum will be followed in the theoretical background. ¬†Theoretical background As we have already learned that Nick Szabo is the computer scientist who has proposed the word Smart Contract in 1994. ¬†However, since then it wasn’t much in use. BlockchainBlockchain is a decentralised data structure in which transactions are recorded by cryptocurrencies. The first work on a cryptographically secure chain of blocks was described in 1991 by Stuart Haber and W. Scott Stornetta. In 1992, Bayer, Haber and Stornetta incorporated Merkle trees to the design, which improved its efficiency by allowing several documents to be collected into one block. The first blockchain was conceptualised by an anonymous person or group known as Satoshi Nakamoto in 2008. A blockchain database is managed autonomously using a peer-to-peer network and a distributed timestamping server. It was implemented the following year as a core component of the digital currency bitcoin, where it serves as the public ledger for all transactions on the network.1 By using a blockchain, bitcoin became the first digital currency to solve the double spending problem without requiring a trusted administrator and has been the inspiration for many additional applicationsCentralised vs decentralised ledgerCryptocurrencyFiat vs CryptocurrencyEthereumDifference between Bitcoin and EthereumSmart contractsWhy should one choose smart contracts than the traditional contracts?Use cases for smart contractsAutomobileBankingCrowdfundingGovernmentHealthcareMusicReal estateSupply chain managementVotingBlockchainCentralised vs DecentralisedCryptocurrencyFiat vs CryptocurrencyBitcoinEthereumBitcoin vs EthereumSmart contractsTraditional vs Smart contractsUse cases