QUALIFIED ELECTRONIC SIGNATURES IN BANKING

DIGITAL TRUST: WHY QUALIFIED ELECTRONIC SIGNATURES HAVE BECOME A STRATEGIC PRIORITY

Digital banking is built on enforceable promises. In the paper world, priorities were anchored by wet-ink signatures, physical presence and manual checks. In the digital world, they must be expressed and protected in software – and banks must be able to prove, sometimes years later, who agreed to what and when.

Qualified electronic signatures sit at the heart of this digital trust fabric. It provides a verifiable link between three elements: the identity of the signer, their intent to be bound, and the integrity of the signed content. That link is backed by strong cryptography, certified hardware security, audited trust service processes and a harmonised legal framework in the form of eIDAS.

For banks operated under eIDAS and eIDAS 2.0, QES is not simply another way to click “I agree” . It is a mechanism recognised by law as equivalent to a handwritten signature, with mandatory cross-border recognition for qualified certificates. This legal effect gives executives a concrete way to translate abstract concepts like digital trust and compliance by design, into specific controls that auditors and regulators can understand and test.

Digital trust in this sense is broader than cybersecurity. It is about being able to demonstrate, to customers and regulators, that the bank knows who it is dealing with, that customers have agreed to specific terms, that those terms have not been tampered with, and that the bank can prove all this efficiently even under scrutiny.

For higher-risk contracts and approvals, using QES as the default control also delivers strong non-repudiation: it becomes significantly harder for any part to plausibly deny that they agreed to or authorised a given action. QES is one of the few tools that addresses all of these dimensions at once.

From a best-practice point of view, banks should deliberately map out which agreements and approvals are critical enough to justify QES – and then make qualified electronic signatures the standard for those cases, rather than treating it as a special exception. At the same time, they should avoid treating QES as the answer to every use case, and instead adopt a transparent, risk-based policy that takes SES, AES and QES into account.

A simple decision framework can help translate this into concrete policies by use case:

• Written-form / high-dispute-risk contracts (for example, lending agreements, guarantees, complex investment mandates, high-value corporate onboarding) - QES as the default, to meet formal requirements and maximise evidential weight.

• Most routine digital consents and lower-risk agreements (such as standard terms acceptance, marketing consents, low-value retail products with clear cooling-off rights) - AES as the default, with SES acceptable where the risk and legal requirements allow.

• Internal approvals and operational actions (for example, workflow approvals, operational signoffs, low-value internal transfers) - typically AES, with selective QES reserved for exceptional, high-risk cases such as large treasury movements or changes to critical security parameters.

Making this framework explicit gives legal, compliance, fraud and product teams a shared reference point and avoids both over-use and under-use of QES.

DATA PROTECTION, FRAUD, AND THE INTEGRITY OF EVIDENCE

From a security and fraud perspective, QES is particularly interesting because it hardens the evidence associated with key contractual events.

In many legacy digital processes, evidence of consent and intent is scattered across log files, database entries, emails and screenshots. The quality and completeness of that evidence can vary. In cases of disputed transactions, alleged account takeover or social engineering, it may be difficult to show that a specific individual agreed to specific terms at a specific time.

This architecture makes evidence strong, structured and portable. The bank can demonstrate, to courts and regulators, exactly who signed what, when, and under which cryptographic and procedural context. Sensitive signing keys are kept away from fragile endpoints, concentrated instead in hardened components that can be certified, monitored and audited. It is easier to implement consistent fraud controls, because the signing step has a well-defined interface that can be monitored for anomalies, linked to risk scoring, and integrated with case management.

These same properties are valuable for high-value transaction approvals.

When customers or internal users authorise large payments, treasury transfers or changes to high-risk settings, using QES for those approvals gives both the bank and the customer stronger protection: the exact transaction details that were approved are cryptographically bound to the signature, strong authentication and the qualified certificate are used at the time of approval, and if the transaction is later disputed the bank has high quality, non-repudiable evidence to support investigations and decisions.

For data protection, this supports the principles of integrity and accountability. The bank can show not just that it protects data in transit and at rest, but that it controls and logs the critical moments where customers consent to the processing of their data and enter into binding commitments.

For fraud management, QES does not eliminate social engineering or credential theft, but it provides a richer, more reliable evidence base for investigations and for assigning liability. A pragmatic recommendation is to define thresholds and scenarios where QES is always required for authorisation - for example, above certain values, in specific channels, or for particularly sensitive changes - and to treat those thresholds as part of the bank’s fraud and non-repudiation strategy.

OPERATIONAL EFFICIENCY AND THE ECONOMIES OF DIGITAL SIGNING

Operational efficiency is often the most visible benefit of moving to qualified electronic signatures, particularly for those responsible for digital change and operations.

Paper signatures introduce friction at every stage, from printing and mailing to manual verification, scanning and indexing, physical archiving, and complex workflows for multi-signer or multi-jurisdiction contracts. Even when these steps are partially digitised, they still depend on manual handling and often create quality issues that surface later in audits or legal disputes.

When a bank deploys a qualified signing capability that can be called from multiple systems, it can embed legally robust signing directly into digital journeys, without building bespoke solutions for each product. Evidence formats and interfaces become standardised, simplifying integration with workflow engines, document management systems and core banking platforms. Manual work in operations is reduced as they become digital from the start and can be validated automatically. Complex multisigner, multi-entity and multi-jurisdiction scenarios can be orchestrated centrally rather than handled as one-off projects.

For teams driving innovation and digital transformation, this architecture also has a direct impact on time-to-market and cost. Once a central signing service is available, new digital journeys can reuse it through well-defined APIs, avoiding fresh integrations or vendor selections each time a line of business wants to digitise a contract. The marginal cost of adding QES to another journey falls, while consistency and control increase.

Operations and compliance teams benefit in a different but equally important way. Today, much of their effort in audits, regulatory reviews and disputes is spent reconstructing proof of compliance: pulling logs from multiple systems, finding copies of documents, checking timestamps and access records. With QES used consistently for key agreements and approvals, a large part of that proof is already present in a single, standardised form. That means less time and money spent assembling bespoke evidence packs, and more confidence that the evidence will stand up to scrutiny.

There is an investment side to QES, but for many banks this is outweighed by reduced paper handling and storage, fewer errors and exceptions, shorter cycle times for onboarding and contract changes, and improved audit and compliance processes. Crucially, QES aligns operational efficiency with control quality: journeys can be both faster and more robust.

HOW CRYPTOMATHIC SIGNER TIES IT ALL TOGETHER

All of these requirements - legal certainty, GDPR alignment, fraud resistance, operational efficiency and support for EUDI Wallets and national eID schemes - point towards a common best practice: a central, policy-driven signing service that can deliver QES across the bank, while remaining invisible to customers.

Cryptomathic Signer is designed to play exactly that role. It provides a single, enterprise signing platform that can be invoked from multiple channels and business systems. Signing keys are protected in hardware security modules (HSMs) and, when used in conjunction with qualified trust service providers and QSCDs, Signer supports the creation of qualified electronic signatures that meet eIDAS requirements.

This gives security and compliance teams confidence that the underlying cryptography, key protection and evidence handling match the bank’s risk appetite and regulatory obligations and support strong non-repudiation for critical agreements and approvals.

Teams responsible for innovation and digital transformation benefit from the fact that Signer is exposed through well-defined interfaces. 

Once the platform is in place, new products, new journeys and new markets, can reuse the same signing service rather than building bespoke integrations or acquiring new tools for each line of business. Time-to-market improves, and the cost of adopting QES in additional journeys falls over time.

Signer can support both document signing (for contracts, mandates, terms and conditions) and transaction approval flows (for high-value payments, treasury transfers or sensitive changes), applying different policies depending on risk and regulatory context. That allows banks to extend the benefits of QES – including non-repudiation and strong evidence – beyond static documents to the moments where money actually moves.

Whether a customer authenticates with bank credentials today, a national eID scheme in one country, or an EUDI Wallet tomorrow, banks rely on Signer and its trust policies to normalise those inputs and produce signatures that meet the required level of assurance and signature type for each jurisdiction and product.

Operationally, Signer provides detailed evidence of each signing transaction, supports audit and reporting needs, and can be deployed in ways that match the bank’s approach to resilience, disaster recovery and cloud or on-premises hosting. In other words, it gives technology, security, compliance, platform and identity teams a practical way to implement the qualified electronic signature without fragmenting the architecture or compromising on customer experience.