Explain distributed ledger technology and where it is used
The idea
A distributed ledger is a shared record maintained by many participants rather than by a central authority, with entries grouped into blocks linked cryptographically so that altering history is detectable and, under proof of work, would require redoing all subsequent work. A consensus mechanism — proof of work, proof of stake or a permissioned equivalent — decides which version is authoritative. Permissionless ledgers are open to anyone; permissioned ones restrict participation and are what most financial institutions actually deploy. The credible applications in finance are settlement, tokenisation of illiquid assets and smart contracts that execute automatically.
A practice question
What is the purpose of a consensus mechanism in a distributed ledger?
- To encrypt the contents of each transactionWhy not: Encryption and hashing are separate functions; consensus decides which record everyone accepts.
- To determine which version of the ledger participants accept as authoritative — correct
- To set transaction feesWhy not: Fees emerge from demand for block space rather than from the consensus rule itself.
Without a central authority, the network needs a rule for agreeing on the record. Consensus is that rule.
A harder one
Why do most financial institutions deploy permissioned rather than permissionless ledgers?
- Because permissioned ledgers are faster to encryptWhy not: Encryption speed is not the constraint; who may participate is.
- Because permissionless ledgers cannot record transactionsWhy not: Recording transactions is exactly what they do, and publicly.
- Because participation must be restricted to known, regulated counterparties — correct
Know-your-customer obligations and confidentiality requirements are incompatible with open participation. The technology is retained; the openness is not.
The hardest tier
What is the potential benefit of tokenising an illiquid asset such as a building?
- Divisible ownership and a transferable record — correct
- It removes the asset's exposure to property pricesWhy not: The token is a claim on the building, so the exposure travels with it.
- It guarantees a liquid market for the tokensWhy not: Divisibility makes liquidity possible rather than certain; many tokenised assets trade thinly.
Both may reduce the cost of trading a claim on the asset. Tokenisation addresses the mechanics of transfer and divisibility, not the demand side: a token on an asset nobody wants is as illiquid as the asset.
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