Blockchain technology offers a data format that has built-in security. It is
built on cryptography, decentralization, and consensus concepts to ensure transaction
confidence. Decentralization is enabled by blockchain technology, which allows
members to participate in a dispersed network. No single user can alter the transaction,
as all transactions are transparent and visible to all other users on the network.
However, there are some significant security differences between blockchain and other
systems. Nowadays, there are so many potential attacks found on the blockchain. The
contribution of this chapter would be to match the effective defence taken by
blockchain technology or a patch for related vulnerabilities offered by researchers to
reduce the impact of these attacks. To keep the network secure and resilient, an
overview of these security solutions for various vulnerabilities and attacks helps to
reduce the attack surface in the blockchain
Keywords: Cryptographic, Decentralization, Consensus, Security, Defense, Attacks
