Digital Signature Asymmetric Cryptography for SignNow

Award-winning eSignature solution

How digital signature asymmetric cryptography works

Digital signature asymmetric cryptography is a method that uses a public key and a private key to prove who signed a document and to detect changes after signing. The signer creates a hash of the document, then signs that hash with a private key. Anyone with the matching public key can verify the signature by checking the hash again. In U.S. business use, this supports identity assurance, document integrity, and nonrepudiation across contracts, approvals, and regulated records.

Why it matters for U.S. signatures

It reduces signing delays, preserves evidence, and supports enforceable electronic records under ESIGN and UETA when consent, intent, and attribution are documented.

Why teams look for DocuSign alternatives

Common implementation challenges

Poor key management can expose private keys and weaken signature trust across contracts and regulated records.
Weak signer authentication makes attribution harder to defend when a document is challenged in court.
Missing audit details can leave gaps in the signing record, including time, device, or identity evidence.
Certificate expiration or revocation can interrupt validation if long-term validation data is not preserved.

Real estate

Real estate teams use it for leases, rental applications, and closing documents that need clear signer attribution.

Healthcare

Healthcare organizations use it for patient forms, consent records, and HIPAA workflows with audit trails.

People who benefit most

A director of NetSuite operations at Xerox uses signNow to route signatures through connected business systems, keeping the right documents in the right format and reducing manual follow-up across finance and operations workflows.
A CEO at Tech Data uses signNow to speed internal and external customer service, where signed approvals, vendor forms, and customer-facing documents need faster turnaround without losing control over compliance and recordkeeping.

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Key pair

The signer’s private key creates a unique signature that can be verified with the public key, helping confirm who signed and whether the document changed afterward.

Document hashing

A document hash turns the file into a fixed fingerprint, so even a small edit breaks verification and reveals tampering.

Audit trail

Audit trails capture signer identity, timestamps, and document events, giving teams a clearer record for disputes and compliance reviews.

Tamper evidence

Tamper-evident sealing helps preserve document integrity after signing, which matters for contracts, approvals, and regulated records.

Public verification

Public key verification lets recipients check signatures without exposing the private key, which supports secure sharing across teams and partners.

PKI support

PKI-based workflows support stronger trust models for documents that need more than a drawn signature or basic electronic approval.

Connected workflows and systems

Connected systems move signed documents into the tools teams already use, reducing manual upload, duplicate entry, and approval delays.

How the signing process works

The signing flow is sequential: create, sign, verify, and record each action so the result can be checked later.

Hash and sign: The signer creates a private-key signature over the document hash.
Verify identity: The recipient checks the signature with the matching public key.
Detect changes: Any document change breaks the hash comparison and fails validation.
Log evidence: The system records signing events for later review and proof.

Quick setup steps

Use a short setup sequence to prepare the file, route it, and preserve the signed record.

Prepare file:
Upload the document and choose the signer.
Configure routing:
Set the signing order and required fields.
Request signature:
Send the request and collect the signature.
Save evidence:
Store the completed record with its audit trail.

Setting	Recommendation
Authentication method	SMS OTP plus ID verification
Signature type	PKI-backed digital 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 support

signNow works in modern browsers and mobile apps, with secure transport over TLS for signing sessions and document access.

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 retention controls matter as much as browser support. Teams should confirm authentication policy, mobile access rules, and any certificate or validation requirements before rollout.

Security and compliance snapshot

Transport security:

TLS 1.2/1.3 protects data in transit

Data at rest:

AES-256 protects stored data

Control assurance:

SOC 2 Type II available

Security management:

ISO 27001 certified

Healthcare compliance:

HIPAA support with BAA

Privacy and trust:

GDPR and eIDAS support

Xerox operations

A Xerox operations leader needed flexible routing across NetSuite-connected workflows and document formats.

Right signatures on right documents

The result was faster routing, clearer document control, and less manual handling across connected business processes.

Tech Data

A Tech Data executive wanted faster internal and external service without losing control over approvals.

Speed to revenue improved

signNow supported quicker turnaround and better customer service while keeping the signing process organized and auditable.

Best practices for secure use

Strong workflows combine identity checks, evidence retention, and controlled access so the signature remains useful after the document is signed.

Match authentication to risk

Use stronger identity checks for contracts, healthcare forms, and financial approvals where signer attribution may be questioned later.

Protect signing credentials

Keep private keys protected and limit access to signing credentials through role-based controls and device policy.

Retain complete evidence

Preserve complete audit trails, including timestamps, signer identity, and document history, for records that may be reviewed later.

Set compliance controls early

Apply encryption, retention rules, and validation controls before rollout, especially for HIPAA, FERPA, and regulated business records.

FAQ and troubleshooting

These answers focus on plan limits, compliance requirements, and signing evidence so teams can resolve setup questions without guessing.

signNow Business includes legally binding eSignatures, audit trails, templates, and mobile apps. For HIPAA use, a BAA is required, and signed records should retain audit evidence and encryption controls.

signNow supports HIPAA compliance when a BAA is in place. The HIPAA Security Rule still requires unique user identification, access controls, integrity controls, and audit controls for PHI workflows.

If a signer cannot complete verification, check the authentication method first. SMS OTP, ID verification, and other stronger methods help attribution under ESIGN and UETA when intent and consent are documented.

For FDA-regulated records, 21 CFR Part 11 requires validated systems, secure audit trails, and unique electronic signatures. signNow workflows should be reviewed against the predicate rule and internal validation procedures.

If a document must be preserved long term, export the completed file and audit trail together. For HIPAA-covered records, retention is 6 years from creation or last effective date, whichever is later.

signNow’s Business plan starts at $8/user/mo billed annually. Enterprise adds advanced signer authentication and integrations, while Site License supports SSO, full API access, and add-ons for HIPAA or 21 CFR Part 11.

signNow	DocuSign	Adobe Sign	PandaDoc
ESIGN and UETA	Yes	Yes	Yes
Audit trails	Yes	Yes	Yes
Starting price	$8/user/mo	$15/user/mo	$14/user/mo
HIPAA support	Yes	Yes	Yes
Envelope cap	No cap	100/year	Not verified

Day 1:

Set up the account, authentication policy, and retention rules.

Day 2:

Send the first document and confirm audit trail capture.

Week 1:

Onboard the team and review signing permissions.

HIPAA retention:

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

Free trial:

signNow offers a 7-day free trial, no credit card required.

Business plan:

Annual billing starts at $8/user/month.

Enterprise rollout:

Advanced authentication and integrations are available on higher tiers.

Record export:

Export completed documents with audit evidence before policy retention ends.

Risks of poor implementation

Weak attribution

Document dispute

Missing evidence

Audit gap

HIPAA failure

Compliance finding

Part 11 issue

Record rejection

Signer authentication:

Verify the signer before the session starts.

Timestamp capture:

Capture the signing time in UTC.

Document hashing:

Hash the document before and after signing.

Tamper-evident sealing:

Seal the record with tamper-evident metadata.

Audit log storage:

Store the event log with the signed file.

Audit export:

Export the audit trail for review or evidence.

	signNow	DocuSign	Adobe Sign	PandaDoc	HelloSign
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	Yes, Business Premium	Not verified	Not verified	Not verified	Not verified
Audit trail	Included	Included	Included	Included	Included
HIPAA compliance	BAA required	Available	Available	Not verified	Not verified

28M+Documents signed

13+Years in business

4.6/5Average G2 rating