Digital Signature Public Key Encryption for Signatures

Award-winning eSignature solution

How digital signature public key encryption works

Digital signature public key encryption is a method that uses a private key to create a signature and a public key to verify it. In practice, the signer’s document is hashed, then that hash is signed with the private key, creating a unique cryptographic record tied to the signer and the file. Anyone with the public key can verify the signature and confirm the document was not changed after signing. In the U.S., this supports secure, attributable electronic signatures and helps preserve document integrity across business workflows.

Why it matters for U.S. signatures

It helps businesses prove who signed, what they signed, and whether the record changed afterward. Under ESIGN and UETA, that evidence supports enforceability, reduces dispute risk, and gives teams a clearer compliance record for contracts, approvals, and regulated documents.

Why teams look for DocuSign alternatives

Common implementation challenges

Weak signer authentication can make attribution harder to defend if a document is challenged later.
Poor key management can expose private keys and undermine the trust model behind the signature.
Missing audit details can leave gaps in who signed, when they signed, and from which device.
Inconsistent retention practices can make it difficult to produce records during audits or litigation.

Business teams

Teams that need attributable signatures use it for contracts, approvals, disclosures, and regulated records.

Regulated documents

Legal, healthcare, finance, and real estate workflows rely on it for secure signing and evidence.

Roles that benefit most

Coordinates NetSuite-connected signature workflows for order forms, approvals, and customer records. This role benefits when signatures must match the right document version and preserve a clear audit record across finance and operations teams, as seen in Xerox’s integration-focused workflow story with signNow.
Manages high-volume contract execution for internal and external stakeholders. This persona values simple signing flows, strong compliance controls, and faster turnaround, similar to Tech Data’s use of signNow to improve service speed and revenue operations across distributed teams.

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Document integrity

Creates a cryptographic link between the signer and the document, helping preserve integrity after signing and making later changes easier to detect.

Signer attribution

Supports signer attribution by pairing identity checks with a verifiable signature record, which helps when records are reviewed or disputed.

Audit evidence

Captures a time-stamped history of signing activity so teams can show who acted, when, and from where.

Faster completion

Reduces manual follow-up by keeping signing steps digital, which shortens turnaround for approvals, contracts, and acknowledgments.

Device flexibility

Works across mobile and desktop workflows, so signers can complete documents without changing the legal record structure.

Compliance support

Fits regulated workflows that need stronger proof of intent, record integrity, and retention for later review.

Connected workflows and systems

Connected systems move signature requests into the tools teams already use, while keeping the signed record, audit trail, and document history intact.

How the signature process works

The process follows a simple cryptographic sequence that signs the document, then lets others verify it without exposing the private key.

Open document: The signer opens the document and reviews the content.
Create hash: The system hashes the file before signing.
Apply signature: The private key signs the hash.
Verify signature: The public key verifies integrity and attribution.

Quick setup steps

Use a short workflow to prepare the file, route it to the right signer, and keep the completed record for review.

Prepare file:
Upload the document and choose the signer.
Configure workflow:
Set the signing order and required fields.
Send for signature:
Send the request through signNow.
Store final copy:
Review the completed record and download it.

Setting	Recommendation
Authentication method	SMS OTP
Signature type	Advanced electronic signature
Audit trail	Time-stamped event log
Document retention	6 years for HIPAA records
Encryption	TLS 1.2/1.3 and AES-256

Platform and device requirements

Use a modern browser or mobile app with TLS support to sign, review, and verify documents across desktop and mobile devices.

Desktop browsers Chrome, Firefox, Safari, and Edge.
Operating systems Windows, macOS, iOS, and Android.
Mobile access signNow mobile apps on iOS and Android.

For regulated deployments, managed devices, SSO, and API access help standardize access and preserve control over signing workflows. Browser and OS support should be paired with retention, authentication, and certificate policies that match the document type and compliance requirement.

Security and compliance snapshot

Transport security:

TLS 1.2/1.3 protects data in transit.

Storage encryption:

AES-256 protects data at rest.

Security assurance:

SOC 2 Type II report available.

Information security:

ISO 27001 certified controls.

Healthcare compliance:

HIPAA support with BAA required.

Privacy and trust:

GDPR and eIDAS aligned handling.

Operations workflow

A NetSuite operations leader needed the right signatures on the right documents.

Xerox used signNow with NetSuite.

The workflow improved document routing and reduced manual signature handling, while keeping the signed record tied to the correct business process. That matters when public key verification and audit evidence must stay aligned with the source system and document version.

Healthcare forms

A healthcare team needed secure patient forms with mobile access and compliance controls.

Fertility Centers of Illinois used signNow.

The team reported strong API support and responsiveness, which helped support secure form collection and record handling. In healthcare workflows, that combination matters because identity, auditability, and retention all affect whether signed records remain usable and defensible.

Best practices for secure signing

A careful setup reduces disputes, preserves evidence, and keeps the signed record usable across business, healthcare, and legal workflows.

Match authentication to risk

Use stronger authentication for contracts, healthcare records, and financial approvals. Pair the signer’s identity check with the document’s audit trail so attribution is easier to defend if the record is reviewed later.

Protect signing credentials

Keep private keys protected and limit who can access signing credentials. A strong public key verification process still depends on secure key handling, access control, and clear user provisioning.

Preserve the full record

Retain the completed file, audit trail, and related consent records together. That makes it easier to respond to disputes, audits, and requests for evidence under ESIGN, UETA, HIPAA, or 21 CFR Part 11.

Control document versions

Use templates and field rules to reduce manual edits after signing starts. Fewer late changes lower the chance of version confusion, broken signatures, or missing evidence in the final record.

Day 1:

Set up signNow Business and verify access controls.

Day 2:

Send the first document for signature.

Week 1:

Onboard the core team and review audit trails.

HIPAA retention:

Keep signed PHI records for 6 years per 45 CFR 164.530(j)(2).

Free trial:

7 days, no credit card required.

Business plan:

$8/user/mo, billed annually.

Part 11 records:

Retain secure audit trails and timestamps.

UETA baseline:

Electronic signatures remain enforceable with attribution and intent.

Risks of poor implementation

Weak attribution

Signature attribution may be disputed.

Poor audit trail

Evidence may be excluded in court.

Missing retention

Records may fail HIPAA review.

Validation gaps

Part 11 records may be rejected.

Signer authentication:

Verifies the signer before the record is accepted.

Timestamp capture:

Records the event time in the audit log.

Document hashing:

Creates a hash of the signed file.

Tamper-evident sealing:

Locks the record against later changes.

Audit record:

Stores the signing history with the document.

Retrieval and export:

Exports the log for review or evidence.

FAQs and troubleshooting

These answers focus on plan limits, compliance needs, and verification issues that affect secure electronic signing in U.S. workflows.

signNow Business includes legally binding eSignatures, audit trails, templates, and mobile apps. If you need bulk send or advanced signer controls, Business Premium or Enterprise adds more workflow options. ESIGN and UETA support the legal framework, while HIPAA requires a BAA for PHI.

signNow supports HIPAA workflows when a BAA is in place. The platform’s security controls, audit trails, and encryption help support PHI handling, but your organization still needs proper access controls, retention rules, and internal policies to meet HIPAA Security Rule requirements.

If a signature looks invalid, check signer authentication, document versioning, and whether the file changed after signing. A tamper-evident record should fail verification if the content was altered. Re-send the document from the signed source file and review the audit trail for the event sequence.

For 21 CFR Part 11 use cases, the system needs secure audit trails, unique user IDs, and two-component electronic signatures. signNow can support regulated workflows, but validation, procedures, and record retention remain your organization’s responsibility under the FDA rule.

The Business plan is priced at $8/user/mo with annual billing. Business Premium adds bulk send, and Enterprise adds advanced signer authentication and integrations. If you need SSO or full API access, the Site License is the plan to review.

If a signer uses a mobile device, the signature can still be valid under ESIGN and UETA when intent, attribution, and consent are captured. signNow mobile apps on iOS and Android help keep the workflow consistent across desktop and phone signing.

Recommended	DocuSign	Adobe Sign	PandaDoc
Audit trails	Yes	Yes	Yes
HIPAA support	Yes	Yes	Yes
Envelope limits	No cap	100/yr	Not verified
Starting price	$8/user/mo	$15/user/mo	$14/user/mo

	Plan / Feature	signNow	DocuSign	Adobe Sign	PandaDoc
Starting price	$8/user/mo	$15/user/mo	$14/user/mo	$19/user/mo	$15/user/mo
Free trial	7 days	Not verified	Not verified	Not verified	Not verified
Bulk send	Business Premium	Plan dependent	Plan dependent	Plan dependent	Plan dependent
Audit trail	Included	Included	Included	Included	Included
HIPAA compliance	BAA required	BAA available	BAA available	Not verified	Not verified

28M+Documents signed

13+Years in business

4.6/5Average G2 rating