An email link can show where a document was sent, but it does not always prove who actually signed it. A signature without authentication introduces uncertainty and weakens document security. Implementing signer authentication enhances trust by verifying the signer’s identity and ensuring signatures are legally valid and securely executed.
Multi‑Factor Authentication for Zero‑Trust eSignatures solve this by requiring every signer to verify their identity at the moment of signing. With authentication methods like Email OTP, SMS OTP, access codes, or ID verification, organizations can reduce fraud, strengthen compliance, and create more defensible signed documents, while BoldSign keeps the experience smooth and friction‑free.
Why zero-trust matters in eSignature workflows
Zero‑trust security follows one core principle: Never trust by default. Always verify.
Email access alone isn’t enough to confirm a signer’s identity. Every signer must verify who they are during signing.
With eSignatures widely adopted across HR, finance, healthcare, and legal teams, organizations need signatures that are:
- Secure
- Verifiable
- Tamper-evident audit trails
This verification‑first approach ensures that every agreement meets those expectations, especially for high‑value or regulated documents.
Authentication vs verification in eSignatures
These terms are often used interchangeably, but they serve different purposes:
- Authentication answers: Who is signing right now? This happens before or during the signing process.
- Verification answers: Is the signed document authentic and unchanged? This happens after signing using audit trails and tamper‑evident records.
Zero‑trust eSignatures require both:
- Strong authentication before signing
- Strong verification evidence after signing
Why “email-only signing” is not enough
For high‑value or regulated documents, organizations need stronger access controls. Zero‑trust signing assumes any single factor can fail, which is why additional authentication steps are essential.
Email links are easy to use, but they don’t prove who is actually opening or signing a document. Risks include:
- Shared inboxes
- Account takeovers
- Accidental or intentional forwarding
Why multi-factor authentication
MFA significantly reduces the risk of unauthorized access and identity fraud. For eSignatures, it provides stronger proof that the signer is exactly who they claim to be at the moment of signing.
Multi‑factor authentication combines two or more signals to confirm identity. For example:
- Email link + one‑time passcode
- Password + phone verification
MFA methods you can apply in BoldSign
BoldSign supports multiple signer authentication options, allowing you to verify signer identity without sacrificing usability.
Email OTP
A one-time password is sent to the signer’s email and must be entered to open the document.
Best for:
- Low to medium risk workflows
- Internal approvals
- Faster adoption with minimal friction
SMS OTP
A one-time password is sent to the signer’s phone via SMS
Best for:
- Medium to high risk workflows
- External agreements where phone possession adds stronger assurance
Access Code
You set a code (PIN) and share it with the signer through a separate channel.
Best for:
- Known parties (repeat vendors, employees)
- Workflows where you want an extra verification step outside email
Identity Verification
Signer identity is verified using additional checks to confirm the signer is who they claim to be.
Best for:
- High‑risk or regulated workflows
- Legal, financial, and compliance‑driven agreements
- Scenarios requiring stronger assurance of signer identity
ID verification for secure eSignatures
BoldSign’s ID verification serves as a high‑security authentication method by validating signer identity before access or signing. By combining government‑issued ID checks with biometric verification, it helps prevent fraud and ensures trust in compliance‑critical and high‑risk workflows.
Highlights:
- Verifies signers using government‑issued photo IDs
- Uses biometric selfie checks to prevent impersonation
- Supports configurable verification frequency and attempt limits
- Enables selective verification for specific signers
- Available across web, mobile, and API‑based workflows
How to implement MFA for every signer in BoldSign
A consistent setup helps teams avoid missed steps.
- Define document risk levels
- Choose a default authentication method
- Apply authentication settings in templates
- Assign authentication to each signer in multi‑signer workflows
- Confirm audit trails capture authentication events
BoldSign gives senders full control over how authentication is applied, making zero‑trust implementation flexible and scalable.
How audit trails complete the zero-trust model
Authentication reduces unauthorized access. Audit trails provide the evidence if questions arise later.
BoldSign audit trails record:
- Who accessed and signed the document
- When each action occurred
- Which authentication method was used
- IP address and device information
- Document integrity through tamper detection
Together, authentication and audit trails support compliance reviews and dispute resolution.
Conclusion
Zero-trust eSignatures make digital signing more than just fast. They make it trustworthy. By requiring every signer to verify their identity before signing and backing each action with a detailed audit trail, organizations can reduce fraud, prevent disputes, and strengthen compliance across critical workflows.
With BoldSign, teams can apply the right level of authentication for every document, from simple approvals to high-risk agreements. Start with a baseline MFA method for all signers, then add stronger verification for sensitive transactions when needed. That way, every signature is not only easy to collect, but also easier to trust.
Make every signature easier to trust. Sign up for a free 30-day trial or connect with our support team for a personalized demo and see how zero-trust signing works in practice.
Related blogs
- Mandating Signer Authentication After Sending Documents via API
- API Key vs OAuth: The Ultimate Guide for Secure API Authentication
- ASP.NET Core JWT Authentication: Setup, Validation, and Best Practices
Note: This blog was originally published at boldsign.comÂ
