Beyond the 1.4 Billion: Designing Digital Payments That Can Survive Offline

Account access is only the starting point

The World Bank’s Global Findex 2021, published in 2022, estimated that 1.4 billion adults did not have an account at a financial institution or through a mobile-money provider. That number matters, but account ownership does not tell the whole story.

A person may have an account and still depend on cash when mobile data is unavailable, electricity is unreliable, a merchant cannot connect to the payment network, or a phone cannot reach the provider’s servers. A visitor with several bank cards can face the same practical barrier in a place where digital acceptance or connectivity is limited.

For financial-inclusion leaders, the wider design question is therefore: Can people safely send and receive value when and where they need to? This can be called transactional resilience. It does not replace account-ownership measures, but it adds reliability, usability and recovery to the definition of meaningful access.

The supplied evidence does not establish a reliable global count for everyone affected by weak transactional resilience. Claims that the addressable population reaches 3.5 to 4 billion should therefore be treated as an unconfirmed estimate, not a measured fact.

What is an offline digital payment?

An offline payment allows a transaction to proceed without an immediate connection to a bank, mobile-money platform or other central system. The devices involved may reconnect later to verify records and update balances.

Research from the Bank for International Settlements and the US Federal Reserve discusses offline payments as a potential way to improve payment-system resilience. It also identifies difficult design questions. While disconnected, a system may be unable to check the latest balance or confirm whether the same digital value has already been spent elsewhere.

Offline capability is therefore not simply an online payment with the internet switched off. It requires rules for:

• how much value can be stored or transferred offline;
• how long a device may remain disconnected;
• how transactions are authenticated;
• how duplicate or manipulated payments are detected;
• what happens when devices reconnect;
• who bears a loss when records conflict; and
• how users recover from a lost, damaged or stolen device.

Where could biometrics fit?

A biometric is a measurable physical or behavioural characteristic, such as a fingerprint or face pattern. In a well-designed system, the biometric can help a device confirm that the authorised person is present.

Biometric-protected cryptography goes further than simply storing a photograph or fingerprint. It can use protected biometric information to help release or reconstruct a cryptographic key. That key can then authorise a transaction or create a digital signature—a mathematical proof that the correct credential approved the payment.

Research on fuzzy extractors, fuzzy vaults, fuzzy commitments and cancelable biometrics explores ways to handle an important problem: biometric readings are never perfectly identical. A finger may be placed differently on a sensor, for example. These techniques aim to reproduce a reliable cryptographic result without treating every scan as exact.

This approach could support offline authentication because the user and device may not need to contact a remote server for every approval. But biometrics do not create money, confirm a live account balance or prevent every form of fraud. They address only part of the offline-payment problem.

Why encryption and template protection matter

Biometric information is sensitive because a person cannot replace a fingerprint as easily as a password. Systems should not treat raw biometric images as ordinary login details.

Biometric template protection converts a scan into a protected representation used for matching. Cancelable biometrics are designed so that a compromised representation can be replaced with a different one, even though the person’s physical characteristic has not changed.

Cryptographic keys also need protection throughout their life cycle: creation, storage, use, replacement and destruction. NIST guidance on key management highlights the importance of managing keys as an ongoing system responsibility rather than a one-time technical step.

Local biometric verification may reduce the need to send sensitive data across a network, but “stored on the device” does not automatically mean safe. Security still depends on hardware, software, access controls, update processes and recovery procedures.

The LOCAL test for responsible design

Leaders can use the LOCAL test as a practical design prompt:

L — Limit offline exposure

Set clear limits for transaction value, cumulative spending and time spent offline. Limits can reduce potential losses, although they may also restrict legitimate use. The appropriate balance depends on the programme and its risks.

O — Operate verification on the device where feasible

Consider whether biometric matching and transaction signing can happen locally without transmitting raw biometric data. Document exactly what leaves the device and what remains stored.

C — Consent and choice

Explain in everyday language what biometric information is collected, why it is needed, how it is protected and how long it is retained. Provide an appropriate alternative for people who cannot or do not wish to use biometrics.

A — Audit and reconcile

Plan how disconnected transaction records will be compared after reconnection. Test duplicate spending, altered device clocks, delayed synchronisation and conflicting balances. Audit trails should support investigation without creating unnecessary surveillance.

L — Loss recovery

Design for lost phones, damaged cards, sensor failure, false rejection and compromised credentials. A payment system is not inclusive if legitimate users can be permanently locked out.

The LOCAL test is a planning suggestion, not a guarantee of security or adoption.

Inclusion requires more than technology

Technical capability does not ensure that people will use or trust a system. Research on technology acceptance highlights perceived usefulness and ease of use. Mobile-money research also shows the importance of service design and the wider acceptance network.

An offline payment option still needs participating merchants, understandable fees, accessible support and clear dispute processes. It must work for people with disabilities, worn fingerprints, shared devices or limited digital literacy. Public agencies and financial providers must also consider data-protection, consumer-protection, financial-integrity and payment-system requirements in each jurisdiction.

No single biometric or cryptographic design is suitable for every population. A public-benefit payment programme, a rural merchant network and a traveller payment product may require different limits, credentials and recovery processes.

What should a responsible pilot measure?

Before scaling, leaders can test a narrowly defined use case and measure:

• successful and failed authentication under real operating conditions;
• payment completion during realistic connectivity outages;
• reconciliation errors and attempted duplicate spending;
• merchant and user understanding of the process;
• exclusion caused by sensor or device limitations;
• time needed to recover access;
• complaints, disputes and loss allocation; and
• the amount of personal data collected and retained.

Results should be reported for the specific country, population, programme and test period. A successful pilot in one setting does not prove that the same model will work elsewhere.

A practical next step

Choose one payment journey that regularly fails when connectivity disappears. Map every step from authentication to later reconciliation, and apply the LOCAL test before selecting technology.

The repeatable lesson is simple: Access opens an account; resilience keeps value moving. Offline biometric protection may become one useful component of resilient payments, but only when paired with transaction controls, privacy safeguards, recovery options, merchant acceptance and accountable governance.