Can Blockchain Make the Financial System Safer?

A payment recorded on a blockchain can be extremely difficult to alter. That does not mean the payment was authorised correctly, the software executed as intended or the person controlling the account was who they claimed to be.

This distinction has become increasingly important as banks, central banks and market infrastructures move beyond cryptocurrency experiments and begin testing tokenised deposits, securities and wholesale settlement. Distributed-ledger technology can provide a shared record of ownership, automate transactions and reduce some of the reconciliation required when several institutions maintain separate databases. It may also enable financial assets and money to move together, reducing the period during which one side of a transaction has delivered while the other has not.

Yet the same technology can create new concentrations of operational risk. A stolen cryptographic key may allow an attacker to approve an apparently valid transaction. A flaw in a smart contract can automate the wrong outcome at machine speed. A bridge connecting two networks can become a single point of failure. Once an incorrect transaction has been finalised, the system’s resistance to alteration may make the loss harder rather than easier to reverse.

Blockchain therefore does not eliminate trust from finance. It redistributes trust among software developers, network operators, custodians, validators, governance bodies and the institutions controlling access to the system.

For banks and financial-market operators, the relevant question is no longer whether blockchain is secure in the abstract. It is whether a particular implementation is safer, more resilient and economically superior to the infrastructure it is expected to replace.

The ledger is only one part of the security model

A blockchain protects records through cryptography, distributed validation and agreed rules for updating the ledger. In a well-designed network, one participant cannot quietly rewrite transaction history without detection or sufficient control over the system.

This can improve data integrity. Several institutions can work from a common record rather than exchanging messages and reconciling separate versions of the same transaction. Ownership changes, payment instructions and compliance conditions can be recorded in a consistent sequence. Auditors and supervisors may gain a clearer history of what occurred and when.

But most successful attacks do not require an attacker to rewrite the blockchain.

They target the points where people and conventional software interact with it. Criminals steal private keys, compromise wallets, exploit poorly written smart contracts, manipulate employees or attack the systems used to approve and transmit instructions. The underlying ledger may continue working exactly as designed while recording a transaction that should never have been authorised.

This is comparable to a bank’s conventional payment database faithfully processing instructions submitted through a compromised employee account. The integrity of the database does not prove the legitimacy of the instruction.

Financial institutions should therefore separate ledger security from end-to-end transaction security. The latter includes identity, access management, custody, transaction screening, software development, network governance, incident response and the legal ability to correct an error.

An institution that focuses primarily on the immutability of the ledger may secure the part of the system that attackers are least likely to target.

Private and public networks present different risks

The term blockchain covers systems with materially different security and governance arrangements.

Public blockchains generally allow a broad population of participants to view transactions, submit activity and, depending on the protocol, take part in validation. Their resilience can benefit from large distributed networks, open-source scrutiny and the absence of one operator capable of unilaterally changing records.

That openness creates difficulties for regulated finance. Banks need to know who their counterparties are, prevent prohibited activity, protect confidential information and satisfy rules concerning sanctions, money laundering and data protection. Transaction fees and network capacity may also vary according to demand.

Permissioned networks restrict participation to approved institutions. Validators, users and data access can be controlled, making the system easier to align with regulatory and commercial requirements. J.P. Morgan’s Kinexys platform, for example, uses permissioned infrastructure to support institutional payments, tokenised assets and programmable settlement.

A permissioned network does not provide the same form of decentralisation as a large public blockchain. Control may be concentrated among a small number of operators, and participants must rely on the governance, continuity and technical competence of the institution running the platform.

This is not necessarily a defect. A bank-led network may offer stronger accountability, customer due diligence and legal recourse than an open protocol. The point is that its security derives partly from regulated institutions and contractual governance, not from decentralisation alone.

Financial companies should examine who can change the software, approve participants, reverse or suspend activity, access confidential data and determine how the network responds to a failure. A system described as distributed can still depend operationally on a small number of administrators, cloud providers or technology vendors.

Tokenisation can reduce settlement risk

One of the strongest financial applications of distributed-ledger technology is not the replacement of money with unbacked cryptocurrencies. It is the tokenisation of existing claims such as bank deposits, government bonds, investment-fund units and other regulated assets.

Conventional securities transactions can involve a chain of brokers, custodians, central securities depositories, clearing houses and payment systems. Each institution records and communicates part of the transaction. Differences among those records must be reconciled, while settlement may take place after the trade has been agreed.

A tokenised platform can combine information about the asset, its ownership and the rules governing its transfer. Programmability can allow payment and delivery to occur as connected parts of the same transaction.

This matters because a financial trade contains two obligations. The buyer must deliver money and the seller must deliver the asset. When these movements are not synchronised, one party may fulfil its obligation while the other fails. Delivery-versus-payment arrangements are designed to reduce that principal risk.

Tokenised money and assets could make such settlement more immediate and programmable. Collateral could also be moved or released according to predefined conditions, potentially reducing manual intervention and allowing institutions to use liquidity more efficiently.

The European Central Bank has already moved beyond theoretical discussion. The Eurosystem’s exploratory work involved 64 market participants and more than 50 trials and experiments examining the settlement of distributed-ledger transactions in central bank money. It has since approved a two-track programme intended to connect distributed-ledger activity with the existing TARGET settlement infrastructure and explore a longer-term integrated solution.

The Bank for International Settlements has similarly argued that tokenised central-bank reserves, commercial-bank money and financial assets could support a more integrated monetary system.

These initiatives do not amount to a wholesale endorsement of every blockchain model. They indicate that central banks see potential value in programmability and common ledgers while insisting that settlement remains anchored in regulated money and sound governance.

Faster settlement can create new liquidity pressures

Near-instant settlement is usually presented as an unqualified improvement. In practice, speed changes how financial institutions manage liquidity.

Under a delayed settlement cycle, firms have time to arrange funding, net offsetting obligations and resolve discrepancies. Real-time or near-real-time settlement can reduce counterparty exposure, but it may require money or securities to be available at the exact moment a transaction is processed.

This can increase intraday liquidity demands. A participant that would previously have settled its net obligation at the end of a cycle may need to finance individual transactions throughout the day.

Programmability can help by coordinating payments and releasing liquidity according to predefined conditions. It can also make failures spread more quickly when the conditions are wrong. A coding error or unreliable external data source could prevent a chain of linked transactions from completing.

Institutions should therefore model liquidity and operational consequences rather than assuming that faster always means safer. The appropriate design may combine rapid execution with queuing, netting, liquidity-saving mechanisms and controlled intervention.

The system must also preserve settlement finality: the legally recognised point at which a transfer becomes irrevocable and unconditional. Technical confirmation on a ledger is not enough if insolvency law, property law or payment legislation does not recognise the same result.

Smart contracts automate both controls and mistakes

Smart contracts are programs that execute predefined actions when specified conditions are met. In finance, they can automate interest payments, collateral movements, corporate actions, compliance restrictions or the exchange of assets and money.

Their attraction is consistency. A properly designed program can apply the same rule repeatedly without waiting for manual processing. It can also embed controls directly into an asset, preventing transfers to unauthorised participants or requiring specified approvals.

The difficulty is that legal and financial obligations are rarely as unambiguous as software assumes.

A contract may need to account for insolvency, fraud, force majeure, disputed data or a regulatory order. An external data provider may report the wrong price or event. The code may implement the written agreement imperfectly. Two correct pieces of software may interact in an unexpected way.

The financial institution must decide which authority prevails when code, contractual documentation and legal obligations produce different answers.

Smart-contract security should consequently involve more than a technical audit before launch. Institutions need formal testing, controlled upgrades, monitoring, segregation of duties and a method of pausing activity when abnormal behaviour occurs. Changes to critical code should require independent approval, and the organisation should know which version of the program governed each transaction.

Automation reduces the time available to recognise an error. The stronger the programmability, the more important it becomes to define emergency powers and human accountability in advance.

Interoperability may become the weakest link

The financial system is unlikely to operate on one universal ledger. Banks, central banks, exchanges, custodians and technology companies are developing different networks for different purposes.

Value will therefore need to move among blockchains and between distributed ledgers and conventional systems. This creates an interoperability problem.

A bridge or messaging layer may lock an asset on one system and represent it on another. If the connecting mechanism is compromised, an attacker may be able to create assets without the corresponding backing or prevent legitimate owners from recovering their property.

Interoperability can also introduce legal uncertainty. An asset may be recognised under one network’s rules but not another’s. Transactions may pass through jurisdictions with different approaches to data, property rights and settlement finality.

The more networks a financial institution connects, the larger its attack surface becomes. A highly secure internal ledger does not protect the institution from weaknesses in an external bridge, wallet provider or data feed.

The security assessment must therefore cover the full transaction route. Management should know which third parties are involved, which systems hold the authoritative record and what happens when two networks disagree.

Immutability can conflict with correction and privacy

The inability to alter historical records is often presented as blockchain’s defining security advantage. Financial systems, however, sometimes need to correct mistakes, enforce court decisions and protect personal information.

A fraudulent payment may need to be frozen. An erroneous asset transfer may require reversal. A court may order ownership to change. Data-protection rules may restrict how personal information is stored or retained.

Institutions can respond by keeping sensitive information off-chain and recording only references or cryptographic proofs on the ledger. Permissioned systems may also give authorised parties the power to suspend transactions or correct defined errors.

These choices weaken the simplistic claim that the system is entirely immutable, but they may make it more suitable for regulated finance. A platform with no mechanism for lawful intervention can be less secure for customers than one with carefully governed administrative powers.

The design question is not whether intervention exists. It is who may intervene, under which conditions, with what oversight and whether every action leaves an auditable record.

What financial institutions should test before deployment

A credible blockchain proposal should begin with the problem being solved. If existing infrastructure already provides secure and efficient settlement, replacing it with a distributed ledger may add cost without creating meaningful value.

The institution should identify which reconciliation, delay, counterparty exposure or manual process the new system will remove. It should compare that benefit with the cost of integration, cybersecurity, legal analysis, governance, training and continued operation of legacy systems.

Security testing should extend from the ledger to wallets, keys, application interfaces, smart contracts and external data. The organisation should test how the platform behaves when a participant is compromised, a validator becomes unavailable, inaccurate information enters the system or two connected networks cease communicating.

Key management deserves particular attention. Institutions need controls over how keys are created, stored, backed up, rotated and recovered. High-value transactions may require several independent approvals rather than one person or system holding unilateral authority.

Boards should also ask who is accountable during an incident. A network involving banks, technology providers and market infrastructures can produce fragmented responsibility. Contracts and operating rules should specify who detects the event, who can suspend the system, how customers are informed and how losses are allocated.

Finally, the institution should establish whether the system remains usable if the blockchain component fails. Financial infrastructure requires continuity arrangements, not an assumption that distributed architecture makes disruption impossible.

Security comes from the whole system

Blockchain can improve the integrity of financial records and reduce some of the risks created by fragmented databases, delayed settlement and manual reconciliation. Tokenisation may also allow money, securities and contractual conditions to operate on the same programmable infrastructure.

None of this makes blockchain a general defence against cybercrime.

The technology can prevent one form of record manipulation while exposing institutions to key theft, coding errors, network governance failures and dependencies on unfamiliar third parties. Its permanence can strengthen auditability while making mistakes harder to reverse. Its capacity for immediate settlement can reduce counterparty exposure while increasing liquidity and operational demands.

The strongest financial applications will therefore be those that use distributed ledgers selectively, within a legal and institutional structure capable of managing the risks surrounding them.

A secure financial system is not created by placing transactions on a blockchain. It is created when the ledger, software, money, institutions and rules for correcting failure operate together.