What is a Blockchain?
Simple Definition of a Blockchain
“The blockchain is an incorruptible digital ledger of economic transactions that can be programmed to record not just financial transactions but virtually everything of value,” Don & Alex Tapscott, authors of Blockchain Revolution (2016).
In simple terms, Blockchain is a distributed and decentralized digital ledger which records transactions across a global network of computers where the information is highly secure. As the name suggests, blockchain is nothing but a linear chain of blocks that holds information of transactions taking place over the web. Every block contains data in the form of coding that is organized in a chronological manner.
At its rudimentary level, blockchain is just a chain of blocks, but not in the traditional sense of those words. When we say the word ‘blockchain’ here, we are basically referring to the digital information (block) stored in a public database (chain). Blocks are dispersed across multiple computers.
Let’s Follow Some Noteworthy Points about Blocks
- Blocks store primary information about transactions, such as date, time, and purchase amount of your last transaction.
- They store information about who the participating entities are in transactions. A block for your purchase from a vendor would record your name. But the catch here is that, instead of using your actual name, your purchase is recorded without any identifying information. In real, a unique ‘digital signature’ is used to refer to your username.
- Also, blocks store apt information that distinguishes them from other blocks in the same blockchain. Each block stores a unique code called a ‘hash’ that allows it to be different from every other block.
A single block on the blockchain can store data depending on the size of the transactions, i.e., a single block can host a few thousand transactions under one roof. Hash codes are used to make sure that blocks in a blockchain are in sync with each other. When too many blocks are connected in a single blockchain, the blockchain size increases. The large network of ledgers (blocks) is what makes a blockchain secure and, therefore, ready and a go-to technology for a widespread business adoption. Unlike a centralized database, in the decentralized blockchain structure, a security breach of just one block or one computer has no major detrimental effect on the whole system.
We have learnt what a blockchain is (take a deep dive through Intellipaat’s Blockchain tutorial). Now that we understand the technology at a basic level, we must discern the myths that revolve around this emerging form of technology.
Here’s what a Blockchain is NOT!
1. Blockchain is not entirely all about bitcoins: Though bitcoin was the first application of blockchains, it has certain fundamental differences from a business-based blockchain.
2. Blockchain is not a product: Blockchain is not particularly a product on sale. Built on the inundation of blocks, the utility of this technology comes from an appropriate set of applications built on top of it.
3. Blockchain is not needed in the absence of a business network: There are cases when a business network collapses or ceases to exist. In these cases, there is no need for a blockchain.
Blockchain is not the replacement of a transaction processing system: Under specific conditions only, blockchain may be used to transform a transaction processing system across a business network. If the following criteria is not on priority, a blockchain implementation is not required at all.
In addition to these points, blockchain is neither a distributed database and secure messaging replacement nor is it usually suited for high-volume and low-value transactions.
When we say Blockchain, we often hear the term ‘distributed ledger technology.’ Here’s the connect between blockchain and distributed ledger technology.
In business language, distributed ledger technology or DLT revolves around an encoded and distributed database which serves as a ledger. In that ledger, records regarding transactions are stored. At the core, DLT is an innovative database approach with a data model wherein cryptography is utilized in each transaction update. Thereby, verification becomes possible across the specific blockchain network, depending on its goal and stakeholders.
In a distributed ledger network, there is no central administration. Rather, there is a shared ownership, making data secure.
H3- Now that we understand Blockchains in a nutshell, let us skim through its variants. Here are the Blockchain variants.
1. H4- Public Blockchain
In public blockchains, distributed ledgers are visible to every user on the Internet. It allows users to verify and modify blocks of transactions in a blockchain. Example: Bitcoin, Ethereum, Dash, and Factom.
2. H4- Private Blockchain
Private blockchains are generally incorporated within single organizations at an intra-level. Specific individuals of the organization are permitted to manipulate transaction blocks. However, anyone from the Internet can view the content of the blocks. But to manipulate the content of blocks, specific permissions are mandatory. Example: Multichain and Blockstack.
3. H4- Consortium Blockchain
With consortium blockchains, things are different. Only a group of organizations or individuals can verify and add transaction blocks. The ledger here may be open or restricted to certain groups only. For its high-security enablement, this variant of blockchain is used by organizations across disparate verticals. Example: Ripple, R3, and Hyperledger 1.0
What are Permissioned and Permission-less Blockchains?
There exist two philosophies in the world of blockchains — permissioned blockchains and permission-less blockchains. Here’s what they are and the underlying difference between them.
Permissioned Blockchains: These blockchains maintain an access control layer to restrict and in some cases allow certain actions to be performed only by select and identifiable participants or individuals. The intrinsic configuration of these blockchains put a check on the transactional activities of participants. Owing to their security aspect, these blockchains are popular among industry-level enterprises and businesses. For instance, a manufacturer may implement a permissioned blockchain for managing supply chains. In this case, third parties including logistic partners and banks may be involved in the whole transaction process. These third parties, may be part of the whole process, ought not to know the actual transaction values. This is where permissioned blockchains pitch in. They restrict transactional control to the manufacturer only.
Permission-less Blockchains: Permission-less blockchains are contrary to what you read above. Here, anyone can join the network and participate in the process of block verification to create consensus. Good examples of permission-less blockchains are Bitcoin and Ethereum blockchains, where any user can join the network and start mining. In permission-less blockchains, the use of Proof of Work (PoW) mining is done. Here, hashing power is offered to build trust. If 51 percent of nodes say that something is true, the output becomes true.
After reading this, one question must have struck your mind. ARE BLOCKCHAINS SECURE?
The answer to this question is the perception of the user. Of course, blockchains are much more secure than traditional technologies, but there is a catch here.
Why do we need blockchains in the first place?
We need blockchains as we do not trust each other with transactions. Therefore, we leverage sophisticated math and innovative software rules that are extremely difficult for threat-attackers to manipulate. However, blockchain is not completely fool proof. With the right set of skills, hackers can easily hack their way through even the best designed blockchain security firewalls.
Blockchains are undoubtedly the most secure form of technology we have presently, but it won’t be far from now when some hacker will eventually find his/her way through our so-called secured blockchains. A lot of research is being done to curb the broken ends that exist in the blockchain world today.
Further, check out the best way to get certified via Blockchain Course and prepare yourself for the best via our Blockchain interview questions.
Originally published at www.intellipaat.com on February 22, 2019.
