What is Blockchain?


Major Components

The term Blockchain refers to a chain of blocks. The blocks are chunks of data. A data block is a chunk of data storing more than one transaction. A Blockchain system is precisely a decentralized distributed system (Bashir, 2017, p.10). It is otherwise a distributed database system. The distribution can be implemented across a peer-to-peer network or by means of a cloud infrastructure. It can also be distributed in an infrastructure through virtual machines of a cloud.

One major component to Blockchain is a node. A node is a system that can be honest, faulty, malicious, and have its own memory and processor in the group of systems defined as an individual player of the distributed system (p.10). Distributed systems are where more than one node works together to represent an outcome to the user a single logical platform. Because distributes systems are complex, the CAP theorem was introduced. The CAP theorem states that any distributes system cannot have consistency, availability, and partition tolerance simultaneously (p.11, p30). Therefore, Blockchain uses a replication of a system state to combine the nodes to achieve consistency, availability, and fault tolerance.
Consensus is a component of Blockchain, most commonly referred to as the Proof-of-Work, which works to agree data between the nodes in replication of the data to the final state. Consensus can be reached through a byzantine fault tolerance based mechanism or a leader based mechanism. Developed in 1982, byzantine fault tolerance is the property of a system to resist failure if some of the nodes fail to communicate or if they act in a malicious way (Demestichas et al., 2020). Nodes must also provide Proof of Stake for Proof of Importance over a Proof of Elapsed Time before being able to participate on the distributed network (Bashir, 2017, p.29).

A connected infrastructure is a main component of Blockchain. The infrastructure can be peer-to-peer network or cloud based. “This is a network topology whereby all peers can communicate with each other and send and receive messages” (p.20). A virtual machine can be a component of Blockchain. Although it is not available on all Blockchains, a virtual machine can be used to run as a smart contract by using Ethereum Virtual Machine (EVM) and Chain Virtual Machine (CVM) (p. 20). Etheruem programming language was specifically created for smart contracts support (Demestichas et al., 2020). Smart contracts are automated autonomous programs that run business logic to execute functions when certain conditions are met (Bashir, 2017, p.23, p.44).

An addresses is another component of Blockchain. Addresses are unique and represent the senders and the receivers usually determined by a public key (p.19, p.69). Uniqueness ensures that every transaction is exclusive. Addresses of the Blockchain are mapped to the Blockchain in a grid fashion. The grid positions can be mutable, but the addresses are immutable (Boardwalktech Inc., 2020). The grid is mapped by coordinates in specifications from the processor. The grid of the Blockchain include further data blocks.

Blocks are another component of Blockchain. Blocks are chunks of data that contain multiple transactions, hashes from the previous block, timestamps, and nonce (Bashir, 2017, p.19). The hashes of previous blocks provide immutability. Immutability in this sense means there is little chance of rolling back changes in the data. If data from a previous block is altered, it will result in a cryptographic link disruption due to the use of different hashes. All of the blocks in the chain will no longer be valid which means they will no longer be connected to the chain. Therefore, it is practically impossible to change a single block in the chain (Demestichas et al., 2020). Grover’s Algorithm provides security in the hashes of Blockchain; and Shor’s Algorithm provide security in discrete logarithm problems (Rodenburg & Pappas, 2017).

“A transaction is the fundamental unit of Blockchain. A transaction represents a transfer of value from one address to another” (Bashir, 2017, p. 19). Values are transferred through tokens (p.22). The transaction is selected and adapted for the data block on one Blockchain node. The data is classified based on criteria to be met for the data block. The data that is selected and classified will be verified to determine if the transaction is valid. Invalid transactions are discarded and valid transactions are queued or otherwise stored (Siemens, 2020). The state machine is a component of Blockchain. Blockchain is a state transaction mechanism that is modified from its initial form to its final form as a result of a transaction execution and validation process by nodes (Bashir, 2017, p. 20).

A programming language is a component of Blockchain. Scripts are commands for the nodes to provide various actions such as transferring values. The security of programming language is an area of importance and ongoing research (p. 20). Programs can run business logic on behalf of users on Blockchain platforms (p.21). KOA, Mandala, Java, and Python are examples of programming languages used by Blockchain.


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Written by Heather Phillips, December 4, 2020