A blockchain is essentially an ever-growing digital list of data records. A list like this is composed of a lot of data chunks that are connected, chronologically ordered, and secured by cryptographic proofs. A blockchain's earliest iteration can be seen in the early 1990s, when physicists W. Scott Stornetta and Stuart Haber, both computer scientists, employed a series of blocks to encrypt data in digital documents to prevent data theft. The work of Haber and Stornetta undoubtedly influenced that of Dave Bayer, Hal Finney, and many other computer scientists and cryptography enthusiasts, and this ultimately led to the creation of the first cryptocurrency. Blockchain technology is a key component of the majority of cryptocurrency networks. It functions as a decentralized, distributed, and public digital ledger that is in charge of keeping a permanent record (chain of blocks) of every transaction that has ever been confirmed. Blockchain transactions are facilitated via a peer-to-peer network of widely scattered computers (referred to as nodes). By maintaining a copy of the blockchain on hand, every node contributes to the network's security and efficiency. As a distributed ledger technology (DLT), the blockchain is specifically designed to be particularly resistant to fraud (like double-spending) and manipulation. This is true because each asset is a very distinct and untraceable type of digital currency and because the crypto blockchain, which acts as a database of records, cannot be altered or tampered with without a prohibitively high cost in terms of electricity and computing power. The network is able to enforce the idea of "original" digital documents as a result. The so-called Proof of Work consensus process allows the Byzantine fault-tolerant (BFT) blockchain to continue operating as a distributed network even if some of the participants (nodes) engage in dishonest activity or have inefficient functionality. Blockchain technology may also be adopted and used in other areas, such as healthcare, insurance, supply chains, IOT, and others. Although it was designed to work as a distributed ledger (on decentralized systems), it can also be used to protect data integrity or save money on centralized systems.