Strategic Financial Management · Digital Finance

Blockchain and Distributed Ledger Technology in Finance

Updated 11 October 2026 · Fact-checked

Blockchain is a type of distributed ledger: a shared record kept by many computers, where transactions are grouped into blocks that are linked by cryptographic hashes. Nodes agree on new blocks through a consensus mechanism. To answer exam questions, define it, describe the type, name the consensus method, and link it to a finance use.

Understand Blockchain and Distributed Ledger Technology

A ledger is a record of transactions. Traditionally one party, such as a bank, keeps it. You trust that party to keep it correct. A distributed ledger technology (DLT) spreads copies of the ledger across many computers, called nodes. Each node holds the same record, so no single party controls it.

Blockchain is the most common form of DLT. Transactions are collected into a block. Each block carries a hash (a fixed-length digital fingerprint of its contents) and the hash of the previous block. This links the blocks into a chain. If someone alters an old transaction, that block's hash changes. The next block's stored hash no longer matches, and the tampering shows. This is why blockchain records are called immutable or tamper-evident. Strictly, they are very hard to change, not impossible.

There are different types. A public blockchain is open: anyone can join, read and validate. Bitcoin is the usual example. A private blockchain is controlled by one organisation, which decides who joins. A consortium blockchain is run by a group of known organisations, such as a set of banks. A hybrid blockchain mixes public and private features. Public chains give more openness and decentralisation. Private and consortium chains give more privacy, speed and control, which regulated finance often needs. Related terms are permissionless (anyone can participate) and permissioned (only approved participants can).

Nodes must agree on which new block is valid. This is done by a consensus mechanism. In Proof of Work, nodes called miners spend computing power to solve a puzzle; the winner adds the block. It is secure but uses a lot of energy. In Proof of Stake, validators lock up their own coins as a stake and are chosen to add blocks; it uses far less energy, and dishonest validators can lose their stake. Permissioned chains often use faster voting-based methods among known participants.

A smart contract is a program stored on a blockchain that runs automatically when set conditions are met. Example: an insurance policy pays a farmer automatically when a trusted rainfall data feed shows rainfall below an agreed level. Uses in finance include cross-border payments, trade finance, settlement of securities, KYC sharing, supply chain finance, insurance claims and tokenised assets. Benefits are speed, lower reconciliation cost, transparency and an audit trail. Limits are scalability, energy use (for Proof of Work), legal uncertainty, privacy, code bugs and the fact that wrong data entered at the start stays wrong.

Key rules to remember

Block linkage: Block n contains: transactions + hash of Block (n − 1) + its own hash; Changing any old block changes its hash and breaks every later link. This is the basis of tamper-evidence.
Smart contract logic: IF condition is met THEN action executes automatically; The condition must be checkable on the chain or through a trusted data source (an oracle).
Public vs private blockchain: Public: permissionless, open, decentralised. Private: permissioned, controlled by one entity, faster, more privacy; Consortium chains are governed by a group of known organisations.
Consensus: PoW vs PoS: PoW: right to add a block comes from computing work. PoS: right comes from stake held; PoW is energy-intensive. PoS uses much less energy.

How to solve Blockchain and Distributed Ledger Technology questions

Blockchain questions are descriptive or case-based. Use one structure and tie every point to the case.

1Read the case and note the business problem: slow settlement, fraud, reconciliation, trust gaps or paperwork.
2Define blockchain or DLT in one or two lines: shared ledger, blocks, hashes, nodes.
3Choose the blockchain type that fits the case (public, private, consortium or hybrid) and give the reason, such as privacy, regulation or number of known parties.
4Name the consensus mechanism that suits it and state why, for example voting among known banks, or Proof of Stake for lower energy.
5Show where a smart contract would automate a step, stating the condition and the action.
6State benefits and limits for this case: speed, cost, audit trail, scalability, legal and privacy issues.
7Close with a clear recommendation in one sentence.

Quickest way: Four-point recall: Type, Consensus, Contract, Caveat

When to use it: Use for short-answer questions and MCQs where you have under two minutes.

Type: who can join? Anyone means public. One owner means private. A group of known firms means consortium.
Consensus: unknown participants point to PoW or PoS. Known participants point to voting-based methods.
Contract: look for an automatic action triggered by a condition. That is a smart contract.
Caveat: add one limit such as scalability, privacy, legal status or bad input data.

Common mistakes in Blockchain and Distributed Ledger Technology

Saying blockchain data can never be changed.
Notes use the word immutable loosely.
Fix: Write that records are tamper-evident and extremely hard to alter. A majority attack or a change agreed by the network is still possible in theory.
Treating blockchain and Bitcoin as the same thing.
Bitcoin is the best-known use.
Fix: Blockchain is the underlying technology. Bitcoin is one cryptocurrency that runs on a public blockchain. Many blockchains have no cryptocurrency.
Calling a smart contract a legal contract by default.
The word contract suggests legal status.
Fix: A smart contract is self-executing code. Whether it is legally enforceable depends on the law and on whether the usual contract elements exist.
Recommending a public blockchain for sensitive bank data.
Students focus on decentralisation only.
Fix: Where privacy, regulation and known parties matter, recommend a private or consortium chain and explain why.
Mixing up Proof of Work and Proof of Stake.
Both names sound alike.
Fix: Work means computing effort and high energy. Stake means coins locked as security and low energy.
Giving only benefits and ignoring limits.
Technology topics feel one-sided.
Fix: Always add at least two limits, such as scalability, regulation, privacy and garbage-in-garbage-out.

Worked examples

Example 1

Five Indian banks want to share trade finance documents and settle letters of credit faster. Suggest the type of blockchain and consensus approach, and explain how a smart contract would help. (6 marks)

Show the solution

Problem: paper documents and repeated reconciliation between the banks cause delay.
Type: the participants are a small group of known, regulated banks, so a consortium (permissioned) blockchain is suitable. Access is limited, and the banks share governance.
Reason: customer data is sensitive and regulators expect identified participants. A public chain would expose data and be slower.
Consensus: a voting-based method among the known banks is suitable. It is faster and uses less energy than Proof of Work, because no anonymous miners are involved.
Smart contract: if the shipping document is uploaded and verified and the goods are marked delivered, payment under the letter of credit is released automatically.
Benefits: shared single record, less reconciliation, faster settlement, audit trail.
Limits: set-up cost, need for common standards, legal recognition, and reliance on accurate input data.

Answer: Use a consortium (permissioned) blockchain with voting-based consensus among the five banks, and a smart contract that releases payment once delivery documents are verified. This cuts delay and reconciliation, subject to cost, legal and data-quality limits.

Example 2

MCQ: A blockchain network allows anyone to join and validate transactions, and new blocks are added by participants who lock up their own coins as security. Which description is correct? (a) Private blockchain using Proof of Work (b) Public blockchain using Proof of Stake (c) Consortium blockchain using Proof of Work (d) Private blockchain using Proof of Stake

Show the solution

Anyone can join and validate, so the chain is public (permissionless). This rules out (a), (c) and (d).
Participants lock up coins as security. This is the stake in Proof of Stake, not computing work.
Option (b) matches both features.

Answer: (b) Public blockchain using Proof of Stake

Exam tips

Expect a short case, such as a bank, payments firm or insurer, and a question asking which type of blockchain to use. Always justify the choice from the case facts.
Write definitions in one line, then spend the marks on application: a use, a benefit and a limit.
Use correct terms: node, block, hash, consensus, permissioned, smart contract. Examiners reward precise vocabulary.
For smart contract answers, always state the condition and the automatic action, with a finance example.
Keep this topic linked to cryptocurrencies, CBDC and cyber risk, since questions can blend them.

Practice questions from Digital Finance

Blockchain and Distributed Ledger Technology in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Blockchain and Distributed Ledger Technology: frequently asked questions

How does blockchain work with a simple example?

Suppose A pays B ₹5,000. The transaction is broadcast to nodes, checked, and placed in a block with other transactions. The nodes agree on the block through consensus, and it is linked to the previous block by its hash. Every node then holds the same updated record.

What is the difference between public and private blockchain?

A public blockchain is open, so anyone can join, read and validate. A private blockchain is run by one organisation that decides who can join. Private chains offer more privacy and speed. Public chains offer more decentralisation.

What are smart contracts in finance?

They are programs on a blockchain that run automatically when agreed conditions are met. Examples are releasing payment on verified delivery, paying an insurance claim on a trigger event, or settling a trade. They reduce manual steps but depend on correct code and correct input data.

Is blockchain the same as DLT?

No. Blockchain is one kind of distributed ledger technology, where data is stored in linked blocks. Other DLT designs may store data in different structures. All share the idea of a ledger kept by many nodes.