Signer Authentication for Secure eSignatures

Verify who signs your documents before they access anything. Choose from email OTP, SMS OTP, access code, Knowledge-Based Authentication, or ID verification based on what each document needs.

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Authentication methods

BoldSign offers multiple authentication options so you can choose the right one for each document.

Email OTP

A one-time password is sent to the signer's email address. They enter it to access the document. Good for general-purpose documents that need a basic identity check.

Email OTP

SMS OTP

An SMS OTP for document signing is sent to signer's mobile number. Ties verification to a physical device rather than just an inbox. Useful for time-sensitive documents.

SMS OTP

Access code

You set a custom code and share it with the signer through a separate channel. Simple and effective when you already communicate securely outside of BoldSign.

Access Code

ID verification

Signers verify their identity using a government-issued ID. Best for high-value contracts, regulated industries, or legal documents requiring strong proof of identity.

ID verification

Knowledge-Based Authentication

Verify signer identity with security questions before document access. Ideal for strong authentication without an ID document.

KBA

Why use Signer Authentication

Security, legal, and procurement teams expect strong authentication controls, which also help protect documents if they’re ever disputed.

Only the right person signs

Only the right person signs

Document access control ensures the intended signer, not just anyone with the link, completes the signing.

Lower fraud risk

Lower fraud risk

Identity verification before signing reduces the chance of impersonation or unauthorized document access.

Full audit trail

Full audit trail

Every authentication event is time-stamped and recorded, giving you a clear record if questions arise later.

Flexible per signer

Flexible per signer

Set a different authentication method for each recipient in the same document. Not all signers need the same level of verification. 

How it works

Setting up authentication takes a few extra steps at the document preparation stage. Here is how the process works from start to finish.

Choose an authentication

Choose an authentication method for each signer. Each can be different

Send the document

Send the document

Each signer authenticates

Each signer authenticates before they can open or sign the document

Authentication events

Authentication events are recorded in the audit trail alongside signature details

Signer authentication via API

BoldSign API supports signer authentication for developers embedding signing into their applications. All four authentication methods are available when creating a document request.

Compare signer authentication options

Choose from low-friction to high-security verification methods depending on your document’s risk level.

Authentication method
Best use case
Priority outcome

Email OTP

Everyday agreements that need a basic identity check and a fast signing experience

Ease matters most

SMS OTP

Time-sensitive documents that need mobile-based verification and quicker completion

Speed matters for mobile-first signers

Access code

Documents shared with signers you already verify through another channel and want flexible control

Ease and flexibility matter most

ID verification

High-value or regulated documents that need strong proof of identity

Enforceability matters most

Security and Compliance

Legally Valid.
Fully Secure.
Always Compliant.

BoldSign meets top global standards like SOC 2, GDPR, HIPAA, and PCI DSS. Every signature is legally enforceable under the ESIGN Act, eIDAS, and global laws. With AES-256 encryption, your data stays protected from start to finish.

Security and Compliance
Customer Stories

Hear from Our Customers

Explore real success stories from organizations that use BoldSign to streamline document workflows, strengthen compliance, and accelerate business operations.

Frequently asked questions

Signer authentication verifies a person’s identity before they can access or sign a document. It adds an extra step, such as a one-time password or ID check, to ensure the right person completes the signing.

No. Authentication is optional and should be used based on the sensitivity of the document. For low-risk agreements, basic verification may be enough. For high-value or regulated documents, stronger authentication is recommended.

Email OTP sends a one-time password to the signer’s email, offering a simple and familiar experience.
SMS OTP sends the code to a mobile number, enabling faster response and tying verification to a physical device for added assurance.

It depends on your priority:
  • For fast and simple signing → Email OTP
  • For quick action and better assurance → SMS OTP
  • For flexibility with known recipients → Access code
  • For strong identity proof and compliance → ID verification
  • For stronger authentication without ID upload → Knowledge-Based Authentication

Use ID verification for high-value, sensitive, or regulated documents where strong identity assurance is required, such as legal agreements or compliance-driven workflows.

You create a code during document setup and share it with the signer through a separate channel. The signer must enter this code to access the document.

Yes. You can assign different authentication methods to each signer within the same document based on their role or the level of verification required.

No. Authentication is quick and efficient, usually taking just a few seconds, so it doesn’t slow down the signing process.

Yes. Authentication methods like OTPs and ID verification help prevent unauthorized access and reduce the risk of fraud by confirming the signer’s identity before signing.

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