## 2 Blockchain Technology  
[PERSON] introduced Bitcoin as an innovative, decentralized, and peer-to-peer cryptocurrency system founded in 2008 [30], which seeks to develop a trustless yet credible financial platform to facilitate transactions through Bitcoins without existing financial institutions or third parties as intermediaries. The fundamental technology is blockchain, which harnesses the strength of peer-to-peer networks, Merkle trees, consensus, and public-keycryptology to maintain high assurance and validity degrees of every transaction and resolve multiple issues [31]. Essentially, a blockchain could be defined as a decentralized, transparent, and transactional database shared among all network nodes (computers) to smoothen the exchange process of various values and media [32; 33]. A conventional database, either relational or object-oriented, employs referential integrity methods to maintain satisfactory data validity and synchronization across numerous copies. Conversely, a blockchain is equipped with a consensus algorithm that determines the block orders and relevant transactions before being included in the ledger. The algorithm automates conflict resolutions, such as double spending, by accepting solely one value as a valid transaction [34]. The latest transaction present in the blockchain repository would be authenticated by the entire node before including the record in a pool of pending transactions. All pending transactions would subsequently be categorized into respective blocks by miners, which are computers that classify and publish the transactions on the blockchain by competing with peers to complete a cryptographic puzzle in acquiring the publication priority. As the puzzle difficulty elevates gradually, feigning transactions on the public ledger would be significantly unlucrative with all nodes ably revalidating the transactions upon receiving the latest blocks. Hence, the blockchain validation feature ensures the mining process is highly secure and fraud-resistant, which contributes high integrity to the public ledger. Each block is timestamped and connected to the previous blocks through hashing to create a sequence of blocks attached to the genesis block (the first block in the network). Hashing is a cryptographic technique that converts all information with various file sizes to a fixed output, namely the hash [35; 36; 37]. Correspondingly, alterations to the original blocks, regardless of minimal or significant, would result in a different hash [38; 39]. Specifically, all stored blockchain data would be subject to several verification stages, which render the information virtually irrevocable and immutable, thus forbidding data tampering even by the initial network entities which publish, process, and store the data. Summarily, the process is performed by miners employing software to decode a relevant cryptogram to publish blocks on the blockchain in guaranteeing network governance [40]. A block is constituted of two main parts, header and body, in which the header contains a previous block hash, timestamp, nonce and Merkle root while the body contains a list of transactions stored in the block. The genesis block is the father of the following blocks in the chain in which it does not contain any previous block hash value nonetheless, genesis block hash is generated by SHA256 hash function, and all subsequent blocks can be traced through it. The previous block's header is hashed via a hashing function in order to be stored in the current block and, thus, blocks are linked, chain growth is increased and simultaneously integrity is preserved against tampering. A timestamp indicates the block creation time, whereas nonce is utilized in the block's production and verification. Merkle tree is a binary tree that contains leaf nodes represented by hashed transactions wherein non-leaf nodes result from the concatenation of its hashed child transactions leading to the production of a Merkle root.