How to Check Digital Signature in PDF with signNow

TL;DR

Use signNow to verify, complete, and manage digital signatures in PDFs securely and in compliance with ESIGN and UETA. Upload a signed PDF, inspect the audit trail and signature metadata, confirm signer identity and certificate details, and store the validated document with encryption and retention controls. For creating or requesting signatures, use signNow's eSign workflows, templates, mobile apps, and API to send for signature, collect authentication, and maintain an evidentiary audit record.

What checking a PDF digital signature means

Checking a digital signature in a PDF means confirming that the signature is authentic, the signer identity is validated, and the document has not been altered since signing. Think of it like checking a tamper-evident seal on a package: the seal shows who packed it and whether someone opened it afterwards. In practice, tools show signature validity, certificate details, signing time, and an audit trail. With signNow, you can inspect these details, verify cryptographic signatures, and manage signer authentication and evidence for legal and compliance purposes.

Why verifying PDF signatures matters

Verifying a PDF digital signature confirms authenticity, preserves evidentiary integrity, and supports legal compliance for electronic transactions. Use signNow when closing remote sales contracts or collecting employee onboarding signatures at scale.

Common verification challenges

• Unsigned or flattened signatures that remove cryptographic metadata break validity checks and require original signed files to verify authenticity.
• Mismatched certificate trust chains can show a signature as untrusted even if the signer is correct, requiring certificate chain inspection.
• Expired or revoked signing certificates produce warnings; extra identity checks or re-signing may be necessary to maintain compliance.
• PDF viewers differ in how they display signature details, so use a consistent tool like signNow for reliable verification and audit records.

Who verifies digital signatures

Organizations use signNow to centralize verification, maintain audit trails, and automate acceptance rules for signed PDFs.

• Real estate brokers verifying lease or purchase agreements prior to closing and recording.
• HR teams confirming offer letters and onboarding forms for compliance and record-keeping.
• Healthcare administrators validating consent and intake forms to meet HIPAA requirements.

Typical user profiles for verification

Alex Kim, IT

An IT administrator configures signNow SSO, enforces two-factor authentication, and monitors encryption keys. They ensure cryptographic protocols like TLS and AES-256 are enforced and integrate signNow with enterprise storage and SIEM tools for secure signature verification.

Maria Lopez, HR

An HR manager sends offer and confidentiality agreements via signNow, checks signature validity and audit trails for each signer, and stores the validated PDFs in a secure folder with retention rules that meet internal policies and regulatory requirements.

Key security and compliance points

Encryption in transit: TLS 1.2/1.3

Encryption at rest: AES-256 encryption

Third-party attestations: SOC 2 Type II

Regulatory compliance: ESIGN and UETA

Health data protections: HIPAA (BAA required)

International standards: ISO 27001 certified

Risks of not verifying signatures

Data breach exposure: Unauthorized access risk

Invalid signature acceptance: Legal challenge risk

Regulatory penalties: Fines or compliance actions

Failed audits: Reputational damage

Contract disputes: Enforceability doubts

Operational delays: Signing workflow stalls

Real-world examples using signNow

Below are condensed case narratives illustrating how signNow is used to check and manage PDF digital signatures in different industries.

Optica Ventures (COO)

Optica used signNow to collect remote investment agreements quickly and reliably.

• They relied on mobile-friendly signing and audit trails to verify each signer.
• The robust signature verification reduced manual follow-ups and compliance checks.

Resulting in faster closings and fewer processing errors for investor documents.

Xerox (NetSuite director)

Xerox integrated signNow with NetSuite to automate approvals and signature verification across procurement workflows.

• The integration preserved signature metadata and chain-of-custody for each PDF.
• Business users could validate signer identity and audit history within their ERP.

Leading to measurable reductions in processing time and stronger evidentiary records for vendor contracts.

Step-by-step: check a PDF digital signature

Follow these clear steps inside signNow to inspect signature status, certificate details, and the audit trail for any signed PDF.

• 01
  Upload Your Document: Open signNow, select Upload, and choose the signed PDF from local or cloud storage.
• 02
  Open Signature Panel: Click the signature badge or audit trail icon to view signature validity and metadata details.
• 03
  Inspect Certificate Details: Review signer identity, certificate issuer, and timestamp information shown in the signature pane.
• 04
  Export Audit Record: Download or save the audit trail PDF and attach it to the validated document in secure storage.

How signature verification works in signNow

signNow uses cryptographic metadata, signer authentication, and recorded events to determine if a PDF signature is valid and untampered.

• Capture signature metadata: The platform records certificate, timestamp, and IP address during signing.
• Validate cryptographic hash: signNow checks the PDF's digest to ensure content unchanged since signing.
• Confirm signer identity: Two-factor or email verification details are cross-checked with the signature record.
• Produce audit trail: A downloadable audit record shows each signing event and verification status.

Core signNow features for PDF signature checks

These primary capabilities support reliable signature verification, evidence collection, and ongoing document management across teams and systems.

Audit Trail

A complete, downloadable audit trail records signer identity, timestamps, IP addresses, and each document event for evidentiary use and compliance reporting.

Certificate View

View signer certificate details and trust chain inside the document viewer to confirm issuer, expiration, and whether the signature remains cryptographically intact.

Mobile Signing

signNow mobile apps allow verification and signing on iOS and Android devices while preserving metadata and enabling offline review with subsequent sync.

Bulk Send

Send one document to many recipients and collect signatures at scale, while each signed PDF retains unique audit trails and signer metadata for verification.

Practical best practices for verification

Adopt consistent processes and controls so PDF signature checks are reliable and defensible across teams and audits.

Define signer order and authentication methods clearly

Set required signer authentication (email, SMS, two-factor) before sending so signNow captures consistent identity evidence at the time of signing, reducing later disputes.

Retain original signed PDFs with audit records

Store the signed PDF and its signNow audit trail together in encrypted cloud storage to preserve tamper-evident evidence and simplify future verification.

Use templates and role-based fields for consistency

Create reusable templates with designated signer roles and mandatory fields to ensure each document captures the same verification data and signing sequence.

Train teams on signature validity checks

Educate legal, HR, and operations staff how to open the signature panel, read certificate details, and export the audit trail within signNow.

Typical verification deadlines and SLAs

Set clear internal deadlines to review and archive signed PDFs so compliance and operational teams act quickly after signature events.

01

Signature review window

48 to 72 hours

02

Dispute notification period

7 to 14 days

03

Retention for transactional evidence

Keep at least 7 years

04

Certificate renewal monitoring

Review quarterly

Common retention and timeline expectations

Organizations should align retention and verification timelines with legal requirements and internal policy to avoid data loss or compliance gaps.

Typical retention period for signed contracts:

Seven years is common for many contract types.

Recommended HIPAA document retention schedule:

Follow healthcare-specific retention rules per state and federal guidance.

Tax records and financial signature retention:

Keep for seven years or as advised by counsel.

Immediate verification timeframe after signing:

Verify within three business days.

Certificate and trust chain review cadence:

Inspect every quarter for expirations.

Expanded features supporting verification

Advanced tools help validate signers, protect documents, and integrate verification into business processes across departments and systems.

Two-factor authentication

Require SMS or authenticator app verification to strengthen signer identity evidence and reduce fraudulent or mistaken acceptances during the signing process.

Conditional fields

Use fields that appear based on signer responses to capture necessary data only when relevant and ensure the audit shows who provided which inputs.

API access

Use signNow API to programmatically upload documents, request signatures, and retrieve audit trails for centralized verification and archival workflows.

Payment collection

Tie signature acceptance to payment collection and record the payment event within the audit trail for complete transaction evidence.

Kiosk and bulk

Collect many signatures in person or at scale while preserving individual audit trails for each signed PDF for verification.

Accessibility compliance

WCAG 2.0 Level AA adherence ensures accessible signing experiences and consistent capture of signature metadata for all users.

How to maintain audit trails

Generate, review, and export audit trails from signNow to support forensic validation and legal defensibility of signed PDFs.

01

Generate Trail:

Open the document and click Audit Trail to build the event log.

02

Review Events:

Scan timestamps, IP addresses, and signer actions for anomalies.

03

Download Record:

Export the audit PDF and attach it to the signed file.

04

Store Securely:

Save both files in encrypted cloud storage.

05

Retain Policy:

Apply retention rules based on document type.

06

Provide Evidence:

Share audit records with legal or compliance teams when needed.

FAQs About checking digital signatures in PDFs

Troubleshoot common verification problems when a signature appears invalid, untrusted, or missing expected certificate details, and learn how signNow addresses these scenarios.

• Why does the signature show as untrusted?
  A signature appears untrusted when the signer’s certificate chain cannot be validated against trusted root authorities. This can happen if the certificate issuer is not recognized, the certificate has expired or been revoked, or the PDF was flattened after signing. To resolve, obtain the original signed PDF, check certificate details in the signature panel, and confirm trust with your PKI administrator or rely on signNow’s recorded authentication evidence.
• What if the PDF was flattened or edited?
  Flattened or edited PDFs can remove cryptographic signature data and make verification impossible. If you receive a flattened file, request the original signed PDF from the sender or ask them to re-send via signNow so the platform preserves the signature metadata and generates a verifiable audit trail.
• How does signNow show signer identity evidence?
  signNow records signer authentication methods such as email verification, SMS codes, and two-factor authentication, plus timestamp and IP address. This evidence appears in the audit trail and signature panel to support identity validation during signature checks and audits.
• Do I need a special viewer to verify signatures?
  You can verify signatures directly in signNow’s web or mobile apps which display certificate and audit details consistently. For external viewers, use Adobe Reader or another PDF tool that supports cryptographic signature inspection, but be aware of viewer-to-viewer display differences.
• What plan supports bulk verification and sends?
  Bulk send and scaled workflows are included in signNow Business Premium and higher plans. For very large volumes, the Site License or Enterprise plans provide usage-based pricing and advanced integrations to automate verification and document lifecycle operations.
• How do I handle HIPAA or regulated documents?
  For protected health information, signNow requires a signed BAA and appropriate plan features. Enable required access controls, two-factor authentication, and retention settings to meet HIPAA obligations and keep auditable evidence for compliance.

Signing lifecycle timeline

Map the typical lifecycle from sending to long-term retention so teams understand when to verify, escalate, or archive signed PDFs.

01

Prepare document

Finalize fields and authentication before sending for signature.

02

Send for signature

Use signNow send options and templates to initiate signing.

03

Signer authentication

Collect identity verification like email or SMS codes.

04

Signature capture

Signer completes fields and signs; metadata is recorded.

05

Verify signature

Open audit trail and certificate details immediately after signing.

06

Download evidence

Export the audit PDF and retain with the signed file.

07

Archive securely

Store encrypted copies with retention rules applied.

08

Periodic review

Review certificates and retention schedules quarterly.

Where you can check signatures

Access verification tools from signNow’s web app, native mobile apps, or programmatically via API endpoints.

• Web browser: Chrome, Edge, Safari supported
• Mobile apps: iOS and Android apps
• API access: REST API for automation

For enterprise deployments, integrate signNow with CRMs, ERPs, and cloud storage to centralize verification and enforcement of signing policies across teams and systems.

Recommended workflow settings for verification

Configure these signNow settings to ensure consistent signature capture, verification, and archival across document workflows.

Feature	Value
Reminder Frequency	48 hours
Signer Authentication Level	Two-factor
Audit Trail Retention	7 years
Automatic Archiving	Enabled
Document Encryption	AES-256

Feature availability across vendors

A concise capability comparison focused on verification-related features for signNow, DocuSign, and Adobe Sign.

Feature comparison across three vendors	signNow	DocuSign	Adobe Sign
Mobile app availability
Audit trail and logs	full audit trail	full audit trail	full audit trail
Bulk send capability	yes, premium	yes, paid plans	yes, select plans
Envelope cap or limits	no cap	100 envelopes/year	varies by plan

Pricing and verification feature comparison (data current as of 2026)

Quick pricing and verification feature snapshot for signNow and four competing vendors. Prices reflect annual billing where available and verification feature availability.

	signNow	DocuSign ($8 ser/mo)	Adobe Sign ($13/user/mo)	PandaDoc ($19/user/mo)	HelloSign ($15/user/mo)
Starting Price	$8/user/mo	$8/user/mo	$13/user/mo	$19/user/mo	$15/user/mo
Free Trial	7-day free trial	Varies by plan	Varies by plan	Varies by plan	Varies by plan
Bulk Send	Yes, Business Premium	Yes, paid plans	Yes, select plans	Yes, paid plans	Yes, paid plans
Audit Trail	Yes, full audit trail	Yes, full audit trail	Yes, full audit trail	Yes, audit logs	Yes, audit logs
HIPAA Compliant	Yes, BAA required	Yes, BAA required	Yes, BAA required	Yes, BAA required	Yes, BAA required
Envelope Cap	No envelope cap	100 envelopes/year	Varies by plan	Varies by plan	Varies by plan