Single-Factor vs Multi-Factor Authentication in E-Signing

What is the difference between authentication and identity verification in e-signing?

Authentication confirms that the signer is the same person who was previously verified, while identity verification establishes who the signer is in the first place.

Identity verification typically occurs before or during onboarding and may involve government ID checks, biometric matching, or database verification. Authentication occurs at the moment of signing and confirms that the verified individual is the one accessing the signing session. Strong e-signing workflows use both. Identity verification without strong authentication still allows impersonation, while authentication without prior verification only confirms access, not true identity.

What happens if a signer fails MFA during the signing process?

The signing session is blocked, and the document remains unsigned until authentication is successfully completed.

Failed MFA attempts typically trigger retry limits, session expiration, or additional verification steps. This prevents unauthorized access while preserving the integrity of the document and audit trail. Failed authentication attempts are usually logged, which can be important for security monitoring and dispute resolution.

Does MFA affect the audit trail of an electronic signature?

Yes. MFA strengthens the audit trail by documenting multiple independent verification events.

Audit logs for MFA-protected signatures include evidence of each factor used, timestamps, IP addresses, device data, and authentication outcomes. This additional context significantly improves traceability and evidentiary value in audits, investigations, or legal disputes compared to single-factor logs.

Is MFA required for cross-border electronic signatures?

Often yes, especially when agreements fall under international or region-specific regulations.

Cross-border agreements are subject to varying legal standards such as eIDAS in the EU or sector-specific requirements in financial and healthcare industries. Many international transactions require higher identity assurance to ensure enforceability across jurisdictions. As a result, MFA or identity verification is commonly required for cross-border e-signing.

Can MFA reduce electronic signature disputes?

Yes. MFA significantly reduces disputes by strengthening attribution and non-repudiation.

When multiple independent factors are required to sign, it becomes much harder for a signer to credibly deny involvement. Organizations that use MFA experience fewer disputes and resolve them more quickly because authentication evidence is clearer and more defensible.

Is single-factor authentication enough for electronic signatures?

Yes, but only for low-risk documents where identity disputes would have no material legal, financial, or regulatory consequences.

Single-factor authentication is generally acceptable for internal acknowledgments, non-binding agreements, or documents that do not create enforceable obligations. In these cases, the primary risk is operational rather than legal.

For any document involving employment, healthcare, finance, personal data, or contractual liability, single-factor authentication is insufficient. If the signer’s email account or password is compromised, there is no secondary control to prevent unauthorized signing. Courts and auditors increasingly view single-factor authentication as weak identity assurance when disputes arise.

Do electronic signatures require multi-factor authentication?

No, electronic signature laws do not universally require multi-factor authentication, but many regulated and high-risk use cases effectively demand it.

In the United States, ESIGN and UETA do not mandate specific authentication methods. Instead, they require that the signer can be reliably identified and that the signature is attributable to that person.

In practice, regulatory frameworks such as HIPAA, PCI-DSS, GDPR, FINRA guidance, and NIST 800-63 strongly favor or explicitly require multi-factor authentication for access to sensitive data and systems. As a result, organizations operating in regulated industries often implement MFA for e-signing to meet compliance expectations and reduce legal exposure.

While MFA may not be legally mandatory in every case, it is often operationally required to satisfy audits, regulators, insurers, and internal risk controls.

Is email authentication secure for signing documents?

No, email authentication alone is not considered secure for high-risk or regulated electronic signatures.

Email-based authentication relies entirely on the security of the signer’s email account. If that account is compromised, forwarded, or accessed by an unauthorized party, the signing link can be used without detection.

Email authentication may be acceptable for low-risk documents, but it provides no protection against common threats such as phishing, business email compromise, or shared inbox access. For any agreement where signer identity must be defensible, email authentication should be combined with a second factor such as an OTP, authenticator app, or biometric verification.

Does multi-factor authentication improve legal enforceability?

Yes, multi-factor authentication materially improves legal enforceability by strengthening non-repudiation and attribution.

Multi-factor authentication provides documented evidence that more than one independent control was required to complete the signing process. This makes it significantly harder for a signer to later deny authorship of a signature.

In disputes, audit trails that show MFA or two-factor authentication was used carry more evidentiary weight than single-factor logs. Courts and arbitrators consistently favor authentication methods that demonstrate reasonable steps were taken to verify signer identity, especially when sensitive or high-value agreements are involved.