Blockchain – Meaning, How It Works & Uses in Finance
Blockchain is a type of distributed ledger technology (DLT). Think of a traditional ledger — a book of accounts maintained by one entity, say a bank.
A blockchain replaces that single book with thousands of identical copies held by participants across a network.
Every time a transaction occurs, it is broadcast to all participants, verified by consensus, and recorded permanently.
The term “blockchain” describes the structure: transactions are grouped into blocks, and each block contains a cryptographic reference (hash) to the block before it, forming a chain.
This makes retroactive tampering computationally prohibitive — changing one block would require recalculating every subsequent block across the entire network simultaneously.
In India, blockchain applications have moved beyond cryptocurrency.
The National Payments Corporation of India (NPCI) has studied blockchain for cross-border remittances, and several public sector banks have piloted it for trade finance and KYC data sharing under RBI’s regulatory sandbox.
Did You Know? The State Bank of India (SBI) joined the BankChain consortium — a network of over 30 Indian and international banks — to explore blockchain-based solutions for trade finance and remittances.
How Does Blockchain Work?
Each blockchain transaction follows a clear sequence:
- Initiation — A user initiates a transaction (e.g., sending cryptocurrency, signing a contract, or recording an asset transfer).
- Broadcasting — The transaction is broadcast to a peer-to-peer network of computers called nodes.
- Validation — Nodes verify the transaction using an agreed consensus mechanism — either Proof of Work (computational puzzle-solving, used by Bitcoin) or Proof of Stake (validators stake tokens as collateral, used by Ethereum post-2022).
- Block formation — Verified transactions are grouped with others into a new block. Each block includes: the transaction data, a timestamp, and a hash of the previous block.
- Chain addition — The new block is added to the existing chain. All nodes update their copy of the ledger.
- Immutability — Because each block references the one before it, altering any historical record would require redoing all subsequent blocks across the majority of nodes — practically impossible on a large, established blockchain.
[INFOGRAPHIC: How a Blockchain Transaction Works — initiate → broadcast → validate → block → chain]
Pro Tip: When evaluating a blockchain-based investment or product, ask which consensus mechanism it uses and how many active nodes it has. A blockchain with fewer than a few hundred nodes is far more vulnerable to a “51% attack” — where one entity gains majority control and can manipulate records.
Key Components of a Blockchain
- Block — The basic unit of storage. Each block holds a batch of validated transactions, a timestamp, its own cryptographic hash, and the hash of the preceding block. The hash linkage is what makes tampering detectable.
- Node — Any computer participating in the blockchain network. Nodes store a full or partial copy of the ledger and participate in validating transactions. More nodes generally mean greater decentralisation and security.
- Hash — A fixed-length cryptographic fingerprint of a block’s contents. Change even one character in the block data and the hash changes completely, breaking the chain.
- Consensus Mechanism — The rule by which all nodes agree on which transactions are valid. The two dominant types are Proof of Work (energy-intensive, used by Bitcoin) and Proof of Stake (energy-efficient, used by Ethereum, Solana, and others).
- Smart Contract — A self-executing programme stored on the blockchain that automatically enforces the terms of an agreement when predefined conditions are met. Used in DeFi, insurance, and supply chain management.
- Private vs. Public Key — Every participant has a public key (visible address) and a private key (secret password). Transactions are signed with the private key and verified against the public key. Losing your private key means losing access to your assets permanently.
Types of Blockchain
Public Blockchain
Open to anyone — anyone can read, write, and validate transactions. Bitcoin and Ethereum are public blockchains.
They are maximally decentralised but slow and energy-intensive. In the investment context, this is where most crypto assets live.
Private Blockchain
Access is restricted to invited participants. A company or consortium controls who can join and validate.
Faster and more efficient than public blockchains, but centrally controlled — which defeats some of the purpose of a distributed ledger.
Used by enterprises for internal record-keeping.
Consortium (Federated) Blockchain
Governed by a group of organisations rather than a single entity. BankChain, the consortium that includes SBI and other Indian banks, is an example.
Balances openness with control — suitable for industry-wide applications like trade finance, insurance claim verification, and KYC sharing.
Hybrid Blockchain
Combines public and private elements. Some data is kept private (accessible only to authorised participants); other data is made public for transparency.
Useful for healthcare records, government land registries, and similar applications where partial disclosure is necessary.
Quick Comparison
Type | Who Can Join | Speed | Decentralisation | Indian Example |
Public | Anyone | Slow | High | Bitcoin, Ethereum |
Private | Invited only | Fast | Low | Enterprise chains |
Consortium | Select orgs | Medium | Medium | BankChain (SBI) |
Hybrid | Mixed | Medium | Medium | Government pilots |
Benefits of Blockchain
- Tamper-resistant record-keeping. Once a transaction is recorded and confirmed, it cannot be quietly altered. For financial applications — cross-border payments, securities settlement, land records — this removes the risk of fraudulent backdating or manipulation. India’s land registry pilots in states like Andhra Pradesh and Telangana have explored this directly.
- Faster cross-border settlements. Traditional international wire transfers through SWIFT can take 1–3 business days and involve multiple intermediary banks. Blockchain-based remittance can settle in minutes, with lower fees — directly relevant for India’s $120 billion annual inward remittance market.
- Reduced counterparty risk in financial contracts. Smart contracts execute automatically when conditions are met — no waiting for a bank to confirm, no risk of the other party reneging. This is particularly useful for derivatives contracts, insurance payouts, and trade finance documents like Letters of Credit.
- Transparent audit trail. Every transaction is time-stamped and visible to all network participants (on public blockchains). Regulators, auditors, and investors can trace the full history of an asset without relying on a single institution’s records.
Risks & Limitations
- Regulatory uncertainty in India. Cryptocurrencies built on blockchain are not legal tender in India. The 30% flat tax and 1% TDS introduced in the 2022 Union Budget apply to crypto gains, but a comprehensive regulatory framework is still pending. Investing in crypto assets carries the risk of sudden regulatory changes.
- Private key loss is irreversible. Unlike a bank account where you can reset your password, losing the private key to a blockchain wallet means permanent loss of funds. There is no RBI, no DICGC, and no customer care number to call. Hardware wallet failures and forgotten seed phrases have cost investors billions globally.
- Scalability constraints. Bitcoin processes roughly 7 transactions per second; Visa processes around 24,000. Most public blockchains still cannot match the throughput of centralised payment systems, which limits their practical use for high-volume applications like UPI-scale payments.
- Smart contract vulnerabilities. Code is only as good as the programmer who wrote it. Bugs in smart contracts have led to major exploits — the DAO hack in 2016 drained $60 million worth of Ethereum. Once deployed on a blockchain, a flawed contract cannot be easily patched.
- Energy consumption (Proof of Work chains). Bitcoin’s annual energy consumption rivals that of some small countries. While Proof of Stake chains are far more efficient, this remains a genuine environmental concern for PoW-based blockchains.
Important: Do not confuse blockchain (the technology) with cryptocurrency (one application of it). Buying a coin because “blockchain is the future” is not an investment thesis — evaluate the specific project, its use case, its team, and its tokenomics separately.
Frequently Asked Questions
What is blockchain in simple terms?
A blockchain is a shared digital ledger — like a Google Sheet that thousands of computers hold simultaneously, where every entry is permanent and visible to all participants.
No single person or company controls it, and past entries cannot be changed without everyone noticing.
What is the difference between blockchain and cryptocurrency?
Blockchain is the underlying technology — the ledger system.
Cryptocurrency is one application built on top of it. Bitcoin uses blockchain to record who owns how many coins.
But blockchain itself can record anything: property deeds, medical records, trade documents, or votes.
Not all blockchains have a cryptocurrency; not all cryptocurrencies add meaningful value beyond speculation.
How secure is blockchain?
Established public blockchains like Bitcoin and Ethereum are very difficult to attack because altering any record would require controlling more than 50% of the network’s computing power simultaneously.
However, the applications built on top — crypto exchanges, wallets, DeFi protocols — are regularly hacked. Blockchain security refers to the ledger itself, not the entire ecosystem around it.
Is blockchain regulated in India?
There is no dedicated blockchain regulation in India as of 2025. Cryptocurrencies face a 30% tax on gains and 1% TDS under the Income Tax Act.
The RBI has explored blockchain for interbank use cases under its regulatory sandbox.
SEBI has examined tokenised securities. A full regulatory framework covering all blockchain applications has not yet been enacted.
Which are the major blockchain companies in India?
Several Indian companies work on blockchain infrastructure and applications.
Polygon (formerly Matic Network), founded by Indian entrepreneurs, is one of the most widely used Ethereum scaling solutions globally.
Other notable names include Primechain Technologies (banking blockchain), 5ire (sustainability-focused chain), and KPMG India and TCS, which offer enterprise blockchain consulting.
The government’s National Blockchain Framework, under the Ministry of Electronics and IT, also drives public sector adoption.
What is blockchain used for in banking?
Indian banks have piloted blockchain for trade finance (replacing paper-based Letters of Credit), KYC data sharing between banks (to avoid repeated documentation), cross-border remittances, and interbank reconciliation.
The RBI’s regulatory sandbox has hosted several blockchain-based fintech pilots.
The efficiency gains are real, but most applications are still in limited production or pilot stages.
Should I invest in blockchain-based products?
That depends entirely on what the product is. Enterprise blockchain solutions adopted by banks are not directly investable instruments.
Cryptocurrencies — the most accessible blockchain investment — carry high volatility, regulatory risk, and no investor protection equivalent to SEBI’s market safeguards.
If you are considering crypto, start with the basics of the specific project (not just “blockchain”), limit exposure to what you can afford to lose completely, and account for the 30% flat tax on any gains under Indian law.