Blockchain shows a huge prospective in the coming future. It is atechnology that provides the possibility of generating and sharing transaction ledgers that are tamper proof. Use cases of Blockchain are enlarging in numbers and width in multiple areas like, Internet of Things (IoT), finance and security. Even though many public and private sectors are introducing this technology, it remains a fear to others due to their lack of familiarity and the point of it not taking any big role in any major security enterprises till now. In this paper we will explain what is a blockchain and define its characteristics, benefits, and the differences between them. And help in choosing the suitable type that accommodates your needs. Then we present the immutability aspect of blockchain and its benefits and compare it with a traditional database. And finally, we will discuss blockchain security (For public and private blockchains) and compare it with a standard cyber security environment and discuss both of them in different cyber-attack scenarios.s.