What is signer authentication?
Signer authentication is how an e-signature service checks that the person signing a document is the person it was sent to. Common methods include a personal link sent to their email address, an access code shared separately, a one-time code sent by text message, and checks of an ID document. The methods used are recorded as evidence.
Also called: Signer identity verification, Recipient authentication, Access code, SMS code
Updated October 15, 2026 · By the PDFZyro team
Common authentication methods
Email is the baseline: the signing link goes only to the signer's address, so whoever signs had access to that inbox. An access code adds something the signer knows: the sender gives it to them another way, such as by phone, and it's never in the email. A one-time code sent by text message adds something they have, their phone. Stronger methods check an identity document, ask knowledge-based questions or use a bank ID or national eID, and are often part of advanced or qualified signatures.
When the signer is in the same room, in-person signing lets a host confirm their identity, for example by checking a photo ID, and record how they did it.
Why it matters
In the United States, the ESIGN Act and UETA don't require a particular method, but a signature has to be attributable to the person, and UETA says that can be shown in any manner, including by the security procedure used. In the EU, eIDAS ties the higher signature levels to stronger identification. If a signature is disputed, the record of how the signer was authenticated, together with the audit trail, is often the key evidence. This is general information, not legal advice.
Choosing the right level
Match the checks to the risk. An email link is usually enough for routine agreements with people you know. Add an access code or a text-message code for contracts with real money at stake, documents sent to an address you haven't confirmed, or signers you've never dealt with. For high-value or regulated transactions, ask whether a specific method, such as an ID document check, is required. Stronger checks take signers a little longer, so use them where they count.
How to authenticate signers in PDFZyro
- Send a signature request. Each signer gets their own link at their email address and doesn't need an account.
- For more, open a recipient's extra checks: add an access code to give them separately, or a mobile number so they must also enter a code sent by text message (on plans that include text-message codes). For in-person signers, you confirm their identity on your device.
- Too many wrong codes lock the request for a while. The checks used for each signer are recorded in the audit trail and on the certificate of completion. PDFZyro doesn't check ID documents.
Tools and guides
Related terms
- Audit trailThe time-stamped record of every step in a signing process, from sending to signing.
- Advanced electronic signature (AES)The middle level of e-signature under eIDAS: linked to one signer and tamper-evident.
- Certificate of completionA summary issued with a signed document showing who signed, when and how they were identified.
- Electronic signature (e-signature)Any electronic sign that shows a person agrees to a document, from a typed name to a drawn signature.