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Choosing the right type of electronic signature is only part of building a reliable signing process. Banks also need to consider how the signer is identified and authenticated, how consent and document integrity are protected, and how evidence can be verified over time.
Trust in electronic signing is built across the entire signing lifecycle. Each stage contributes to the reliability of the final result, from establishing who is signing and capturing informed consent to protecting the signed document and preserving evidence. This article looks at six components banks should consider when building a trustworthy electronic signing process.
1. Establish a Trusted Identity
Trust in a signing process starts before the signature event itself. A signature is only as credible as the identity behind it.
For banks, establishing that identity may involve document verification and biometric matching during digital onboarding, an existing verified customer relationship, or another trusted identity source. Once identity has been established with sufficient assurance, the bank has a foundation it can rely on for future interactions, including signing.
Device binding extends that foundation further. By linking the customer to a trusted device, banks can increase confidence that future signing events are performed by the right person.
2. Authenticate the Customer Before Signing
Identity establishment and authentication are different things. Establishing identity happens once at onboarding. Authentication confirms at each signing event that the right person is completing it.
A signing flow that relies on an existing login session without a dedicated authentication step provides weaker assurance than one where the customer actively confirms their identity before the signature is applied.
Depending on the document, risk level, and applicable requirements, multi-factor authentication combining a bound mobile device with biometric or PIN confirmation can provide a strong foundation for the signing flow. Phishing-resistant methods, including FIDO2-based credentials and device-bound keys, are worth considering here. In a signing context, stronger authentication increases confidence that the signing event can be attributed to the intended person.
The EUDI Wallet provides another option for electronic signing. Under the European Digital Identity Framework, EUDI Wallets can support qualified electronic signatures, giving banks another way to enable signing alongside existing approaches such as mobile app authentication or FIDO2.
3. Capture Clear and Informed Consent
A signature that cannot be shown to represent genuine, informed consent has limited value regardless of the technical mechanisms behind it.
The customer needs to have had a meaningful opportunity to review the document, understand what they are agreeing to, and take a deliberate, explicit action to confirm it. A flow where the customer sees a summary rather than the actual document, or where the confirmation step is easy to miss, is weaker on consent grounds even if the signing mechanism is technically sound.
Banks should therefore treat consent capture as an important part of the signing process, not simply as a UX detail.
4. Protect Document Integrity
A signed document is only meaningful if it can be shown that nothing has changed since it was signed.
Digital signatures use cryptographic mechanisms to protect document integrity. They allow changes to the signed content to be detected during validation, providing evidence that the document has not been altered since it was signed.
PAdES is widely used for banking document signing in Europe. It embeds the signature and verification data directly into the PDF, keeping the document and signature bound together regardless of where the file is stored.
5. Create Verifiable Evidence
The audit trail is what makes a signing event defensible. In a dispute or regulatory review, the question is not just whether a signature exists but whether it can be demonstrated who signed, when, and under what conditions.
A robust audit record should capture the signer's identity, the time and device used, the authentication method used, and the document version presented. That evidence should be protected against alteration, retained appropriately, and retrievable when needed.
Whatever form the audit evidence takes, it should provide a reliable record of the signing event and remain available for future verification, disputes, or regulatory review.
6. Preserve Trust Throughout the Document Lifecycle
A signed document needs to remain verifiable long after signing. This is where many implementations fall short.
Certificates expire. Algorithms evolve. Systems are replaced. A document signed today using a certificate that expires in two years needs additional mechanisms to remain verifiable in ten years.
Long-term validation (LTV) preserves the information needed to validate a signature over time, including relevant certificate and revocation information. Trusted timestamping provides independent evidence that the signed data existed at a particular point in time. Together, these mechanisms help preserve the ability to verify the document over time.
The cryptography protecting the signature also needs to remain secure throughout the document's lifetime. As quantum computing advances, today's widely used public-key algorithms may eventually become vulnerable, raising particular concerns for documents that need to remain trustworthy for many years. Post-quantum cryptography provides a way to address this longer-term risk using algorithms designed to resist attacks from both classical and quantum computers.
7. Trustworthy Signing as a Connected Process
These six components form a chain. A weakness in any one of them affects the reliability of the whole. Strong authentication does not compensate for weak identity proofing. Good document integrity mechanisms do not help if consent capture is legally questionable.
Banks that approach electronic signing as a connected process rather than a set of features tend to produce implementations that hold up better under scrutiny.
Wultra's electronic signature solution covers identity-backed signing, strong authentication at the point of signature, PAdES-compliant document integrity, and long-term auditability and validation within a single mobile SDK, designed to sit inside existing banking infrastructure rather than alongside it.
Frequently asked questions
Does the authentication method affect the evidential strength of a signing event?
Stronger authentication can increase confidence that a signing event can be attributed to a specific individual. Device-bound, biometric-confirmed authentication, for example, can provide stronger evidence of who approved the signature than a simple login session. However, stronger authentication does not by itself give an electronic signature a higher formal legal status.
What is long-term validation, and why does it matter?
Long-term validation (LTV) preserves the information needed to validate a signature over time, including relevant certificate and revocation information. This helps preserve the ability to verify signed documents in the future, including after the signing certificate has expired.
What should a banking audit trail for a signing event contain?
At minimum: the signer's identity, the time and device of the event, the authentication method used, the document version presented, and evidence supporting the integrity of the signing event. The evidence should be protected against alteration, retained appropriately, and retrievable when needed throughout the applicable retention period.
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