What Is a Digital Signature? Digital Signature vs. Electronic Signature

What Is a Digital Signature? How It Works in 2026

A digital signature uses cryptography to help verify that electronic data came from the expected signing key and has not been altered. It is different from the broader concept of an electronic signature, which is an electronic method used to indicate a person’s intent to sign. Whenever someone needs to sign a document electronically, understanding these distinctions helps them choose the right method.

A digital signature is a cryptographic method used to verify the authenticity and integrity of digital messages or documents. It uses a private key to create the signature and a corresponding public key to verify it. This approach is a direct application of public-key cryptography.

When the signing key is reliably linked to an identity through a trusted digital certificate, the certificate can provide additional assurance about the identity associated with that key. Without a trusted certificate linking the key to a verified identity, a signature can confirm integrity but not necessarily who signed. These certificates are typically issued by a trusted third party rather than self-issued by the signer.

According to NIST’s Digital Signature Standard, digital signatures can help detect unauthorized modifications to data, authenticate the identity of the signatory, and support non-repudiation by providing evidence that the signature was generated by the claimed signatory. In this way, digital signatures support both security and legal accountability in digital transactions.

That makes a digital signature different from a scanned handwritten signature, typed name, or visual signature pasted onto a document.

It is also important to distinguish a digital signature from the broader category of electronic signatures. In document-signing workflows, a digital signature is a cryptographic technique that can be used within an electronic-signature process. The same public-key technology can also be used to encrypt messages for confidentiality, a related but separate application of cryptography.

For legal, procurement, HR, finance, and contract teams, understanding that difference can help determine the appropriate signing method for different agreements.

A standard electronic signature may be suitable for many everyday transactions, while higher-value, regulated, cross-border, or dispute-sensitive documents may require stronger identity verification, tamper evidence, or a particular type of electronic signature under applicable law. A Qualified Electronic Signature, for example, is a specific type of electronic signature that carries additional legal weight in the EU.

For a broader overview of signing methods, see the Complete Guide to Digital Signatures, Email Signatures, and Online Contract Signing (2026).

Important: This article provides general information and is not legal advice. Electronic and digital signature requirements can vary by jurisdiction, document type, transaction, and applicable regulation.

How Does a Digital Signature Work?

Digital signatures are built on public-key cryptography. This underlying framework of keys, certificates, and trust relationships is commonly known as PKI.

In simple terms, the signer uses a private key to create a digital signature, while the corresponding public key allows another party to verify it. NIST describes a public key as the public part of an asymmetric key pair that can be used to verify a digital signature generated using the corresponding private key.

The process generally works in four steps.

1. The Document Is Hashed

A cryptographic hash function processes the document and creates a fixed-length mathematical fingerprint of its contents. Secure hash functions are designed so that even a small change to the document produces a different result, while accidental matches between different inputs are extremely unlikely.

If the document changes after signing, the resulting fingerprint will also change.

2. The Private Key Creates the Signature

A digital-signature algorithm uses the signer’s private key and information derived from the document to generate the signature.

The signing format may also include or reference certificate or key information that helps the recipient’s software determine which public key should be used for verification.

The private key must remain protected and under the control of its authorized holder. During verification, the recipient’s software uses the public key, the signature, and the signed data to mathematically determine whether the signature is valid.

Strong key-security practices, such as hardware-based storage, help prevent unauthorized use of the private key.

3. The Signature Accompanies the Document

The signature information is associated with the signed document.

Depending on the signing system, certificate information may also accompany the signature to support verification and help establish the identity associated with the signing key.

4. The Public Key Verifies the Signature

The recipient’s software uses the corresponding public key to verify the signature. Verification does not decrypt the original document; it mathematically checks whether the signature matches the expected result.

If the signed content has been altered in a way that affects the signature, verification should detect the change. A successful verification result indicates that the document has not been altered since it was signed.

This provides tamper evidence that a visual handwritten or scanned signature cannot provide on its own. Recipients can generally trust that a document with a digital signature has not been altered since signing, provided verification succeeds.

A digital signature can therefore help verify document integrity and authenticate the signing key. When that key is reliably connected to a verified identity, it can also provide stronger evidence about who signed.

When combined with trusted timestamps, certificate information, or an audit trail, the signing process can also provide evidence about when and how the document was signed.

Digital Signature vs. Electronic Signature: What’s the Difference?

The terms electronic signature and digital signature are often used interchangeably, but they are not identical.

An electronic signature is the broader category. Depending on the system and jurisdiction, it can include a typed name, click-to-sign action, drawn signature, or other electronic method used to indicate signing intent.

In everyday use, people often shorten “electronic signature” to e-signature or e-sign. In short, an electronic signature is an electronic indication of intent, while a digital signature adds cryptographic verification on top.

A digital signature uses cryptographic technology to provide technical verification of authenticity and document integrity and may be used within an electronic-signature process.

Note that signing does not necessarily encrypt the document itself, since encryption and signing address different security goals.

A wet signature is a traditional handwritten signature made with ink on a physical document.

An email signature usually means the block containing a person’s name, title, company, logo, and contact details at the bottom of an email. That type of footer is not, by itself, a cryptographic digital signature.

Signature Type	What It Is	Verification	Legal Considerations	Typical Use
Wet signature	Handwritten signature on a physical document	Usually visual or evidence-based	Some transactions may still require paper, witnesses, or notarization	Physical documents and specific formal transactions
Electronic signature	Electronic data or an action used to indicate signing intent	Depends on the signing method	Generally recognized in many jurisdictions when applicable requirements are satisfied	NDAs, employment documents, vendor agreements, routine contracts
Digital signature	Cryptographic technique using public/private key technology	Cryptographic integrity and key-based verification	Can provide stronger technical evidence; legal effect depends on applicable law and signing process	Higher-assurance contracts and regulated workflows
Email signature/footer	Static name, title, logo, and contact details	No cryptographic verification by itself	Whether an email constitutes an electronic signature depends on context and intent	Branding and contact information

The simplest distinction is:

Electronic signature = electronic indication of signing intent.

Digital signature = electronic signing supported by cryptographic verification.

Not every electronic signature uses digital-signature technology. It also helps to remember that digital signing is distinct from encryption, which protects confidentiality rather than authenticity.

For legal and procurement teams, the appropriate method depends on the agreement, parties, internal risk requirements, jurisdiction, and any applicable regulatory requirements.

What Is a Digital Certificate?

A digital certificate is an electronic credential that associates a public key with identity information about a person or organization. In a signing context, this is often called a signing certificate.

Technically, a digital certificate is an electronic document issued and signed by a trusted authority.

NIST defines a public-key certificate as a set of data that identifies a public key and an owner authorized to use the key pair, and that is digitally signed by a trusted Certification Authority, thereby binding the public key to the owner.

In practice, this means the certificate must be issued by a trusted certificate authority recognized within the relevant trust framework. NIST’s definition specifically refers to this as a public-key certificate rather than a general identity document.

Many enterprise signing platforms use public key infrastructure to manage certificates at scale.

In trusted digital-signature environments, certificates can therefore help establish the relationship between the signing key and the identity associated with it.

These trust relationships are managed through what is known as public key infrastructure. In identity-based signing frameworks, certificate issuance typically follows an identity-validation process appropriate to the certificate type and required assurance level.

Certificates and related trust services are typically issued or managed by certificate authorities or trust service providers. A certificate issued by a certificate authority typically includes the identity details and public key needed for verification.

For legal, procurement, and contract teams, these technical elements are generally handled by the selected signing or trust service rather than manually managed as part of the everyday contract workflow.

The exact certificate, identity-verification, and trust requirements depend on the signing service, transaction, jurisdiction, and required assurance level.

Are Digital Signatures Legally Binding?

Digital signatures can be legally valid and enforceable, but their legal effect depends on factors such as:

• jurisdiction;
• document type;
• intent to sign;
• authority to sign;
• consent where applicable;
• identity and attribution;
• record-retention requirements; and
• transaction- or industry-specific formalities.

Using digital-signature technology does not automatically make every document legally enforceable.

Digital signatures are legally recognized as valid evidence in many jurisdictions, but the surrounding requirements still matter.

Electronic and Digital Signatures in the United States

Under the federal Electronic Signatures in Global and National Commerce Act (E-SIGN Act), a signature, contract, or other record relating to a transaction in or affecting interstate or foreign commerce may not be denied legal effect, validity, or enforceability solely because it is in electronic form.

The Uniform Law Commission describes the Uniform Electronic Transactions Act (UETA) as establishing the legal equivalence of electronic records and signatures with paper writings and manually signed signatures, helping remove barriers to electronic commerce.

However, organizations must still consider the legal requirements applicable to the underlying transaction.

Certain documents and transactions may also be subject to exclusions or additional formalities.

Electronic and Digital Signatures Under eIDAS

The eIDAS Regulation establishes the European Union’s framework for electronic identification, electronic signatures, and trust services.

It distinguishes between three commonly referenced levels of electronic signature:

• Simple Electronic Signature (SES)
• Advanced Electronic Signature (AdES)
• Qualified Electronic Signature (QES)

Under Article 26 of eIDAS, an advanced electronic signature must be uniquely linked to the signatory, be capable of identifying the signatory, be created using signature-creation data under the signatory’s sole control with a high level of confidence, and be linked to the signed data so that any subsequent change is detectable.

A Qualified Electronic Signature (QES) is an Advanced Electronic Signature created using a qualified electronic signature creation device and based on a qualified certificate for electronic signatures.

These additional requirements distinguish QES from other electronic-signature levels under eIDAS.

Under Article 25 of eIDAS, a qualified electronic signature has the equivalent legal effect of a handwritten signature.

However, a cryptographic digital signature does not automatically qualify as a QES. The signing service, certificate, transaction, and applicable regulatory requirements still matter.

Digital Signatures in Saudi Arabia, the UAE, and Qatar

Electronic and digital signatures are also governed by national legal frameworks across GCC markets. These frameworks generally extend legal recognition to digital documents and transactions conducted electronically.

Saudi Arabia

Saudi Arabia’s Electronic Transactions Law establishes a legal framework for electronic transactions and electronic signatures, including the use and reliability of electronic records.

Organizations should assess the applicable requirements based on the transaction, document, and level of authentication required.

United Arab Emirates

The UAE regulates electronic transactions and trust services under Federal Decree-Law No. 46 of 2021 on Electronic Transactions and Trust Services.

The framework covers electronic documents, electronic signatures, electronic seals, trust services, qualified trust services, and procedures related to electronic transactions.

Qatar

Qatar’s Decree Law No. 16 of 2010 Promulgating the Electronic Transactions and Commerce Law establishes a legal framework addressing electronic transactions and electronic signatures.

Qatar’s Al Meezan Legal Portal lists the law as currently in force.

Benefits of Digital Signatures

For organizations handling contracts and approvals at scale, digital signatures can provide several advantages over paper-based processes and less sophisticated signing methods.

Moving these steps into digital workflows can also reduce delays associated with printing, scanning, and manual routing.

1. Stronger Integrity and Authentication

Digital signatures can help recipients determine whether signed content has changed after signing.

According to NIST, a properly implemented digital signature can provide mechanisms for origin authentication, data integrity, and signatory non-repudiation.

As noted earlier, digital signatures rely on public and private key pairs, which is what allows this kind of independent verification.

When combined with appropriate identity verification, digital signatures can also provide stronger evidence linking the signing activity with an identified person or organization.

2. Better Auditability and Evidentiary Records

Depending on the signing service and configuration, enterprise signing environments may preserve information such as:

• signer identity;
• date and time;
• signing sequence;
• document version;
• authentication events;
• verification status; and
• completion status.

Digital-signature workflows can therefore strengthen the technical and evidentiary record surrounding the signing process.

This does not eliminate every possible dispute or security risk, but it can provide stronger technical evidence than a scanned signature image alone.

3. Faster Contract Execution

Electronic and digital signing workflows can remove many of the manual steps associated with paper signatures.

Instead of:

Print → sign → scan → email → download → re-upload → archive

contracts can move from approval into signing and then into a centralized contract-management process.

For legal and procurement teams managing large contract volumes, removing these handoffs can reduce administrative friction and accelerate execution.

Where Are Digital Signatures Used?

Digital signatures can be useful where organizations require stronger assurance around document authenticity, integrity, or authorization.

Adopting digital signature technology in these areas can help organizations reduce reliance on manual, paper-based verification. They are increasingly relied on across digital documents and transactions in both public and private sectors.

Legal Contracts and NDAs

Digital signatures may be used for:

• master service agreements;
• confidentiality agreements;
• supplier agreements;
• commercial contracts; and
• other agreements where stronger evidence around the final executed document is desirable.

Procurement and Vendor Contracts

Procurement teams can combine digital signing with:

• stakeholder approvals;
• controlled contract workflows;
• audit trails;
• vendor agreements; and
• centralized contract repositories.

This is particularly useful when multiple departments need to review or approve an agreement before execution.

Financial Services

Financial organizations may use digital-signature technologies for agreements, approvals, and other records requiring stronger controls around identity, authorization, or integrity.

The appropriate signing method will depend on the financial transaction and applicable regulatory requirements.

HR and Employee Agreements

Electronic and digital signatures can support employment workflows involving documents such as:

• offer letters;
• employment agreements;
• NDAs;
• policy acknowledgments;
• benefits documentation; and
• internal approvals.

However, HR teams operating across multiple jurisdictions should not assume that the same signing method is appropriate for every employee document.

Requirements should be evaluated by document type and jurisdiction, particularly for regulated, immigration-related, government, or other formally controlled documents.

Government Transactions

Digital signatures may also be used in government applications, filings, approvals, licensing, and other electronic processes requiring stronger identity or document-integrity controls.

The exact requirements depend on the relevant public authority and jurisdiction. In government use cases, a digital signature is sometimes paired with a broader digital ID system to verify who is submitting a filing.

How to Choose the Right Signing Method

There is no single signing method that is appropriate for every contract.

Organizations should consider both the legal requirements of the transaction and how signing fits into their wider contract process.

Situation	What to Consider
Routine business agreement	A standard electronic-signature method may be sufficient depending on applicable requirements
High-value or sensitive agreement	Stronger identity verification and tamper evidence may be appropriate
Regulated transaction	Check jurisdiction-specific and industry-specific signing requirements
Cross-border agreement	Consider the legal requirements of all relevant jurisdictions
Large contract volume	Consider how signing connects with approvals, storage, reporting, renewals, and obligations
Multiple internal approvers	Look for a process that connects approval workflows with execution rather than treating signing as a separate step

The signing method itself is only one decision.

Organizations also need to determine how the contract moves through creation, review, approval, execution, storage, and post-signature management.

The specific certificate, identity-verification, and trust requirements depend on the selected signing service, transaction, and jurisdiction.

For contract teams, the more operational question is how that signing service connects with everything happening around the signature.

Why Digital Signing Is Only One Part of Contract Management

A digital signature can address authenticity and integrity at the execution stage.

But execution is only one stage of the contract lifecycle.

Before a contract is ready for signature, teams may still need to:

• create the agreement;
• select the appropriate template;
• negotiate clauses;
• review risks;
• collect stakeholder comments;
• route approvals;
• manage versions; and
• confirm signing authority.

After signing, teams still need to:

• store the executed agreement;
• track obligations and deliverables;
• monitor deadlines;
• manage renewals;
• handle amendments;
• maintain records of contract activity; and
• report on contract activity and performance.

That creates an important distinction:

A digital signature helps solve the execution problem. Contract Lifecycle Management helps solve the broader contract lifecycle problem.

When signing is isolated from the rest of the contract process, teams may still rely on separate inboxes, repositories, spreadsheets, approval tools, and manual follow-up.

Connecting signing with the processes before and after execution can give legal, procurement, HR, finance, and other contract stakeholders better visibility throughout the agreement lifecycle.

How Lexzur CONTRA Connects Signing to the Contract Lifecycle

Lexzur CONTRA supports electronic and digital signing as one part of a broader Contract Lifecycle Management and document automation workflow.

CONTRA connects contract workflows with supported electronic and digital signing services, some of which use digital-signature and certificate technologies to provide additional integrity and authentication controls.

Rather than operating as a standalone certificate authority or trust-service provider, CONTRA connects contract workflows with supported signing services and integrations.

According to Lexzur’s signing documentation, available signing workflows include Lexzur Sign, DocuSign, Adobe Sign, Emdha, Sirar, and other digital-signature workflows available through Lexzur and its Marketplace.

Before an agreement reaches signature, teams can use CONTRA to:

• create agreements from templates;
• collaborate on reviews and redline agreements;
• manage negotiation;
• manage document versions; and
• route contracts through configurable approval processes.

Once the contract is ready, it can move into the appropriate electronic or digital signing process through the selected signing service.

For example, Lexzur documents a dedicated DocuSign integration through which contract signing status and completed documents can be connected back to the contract record in CONTRA.

After execution, teams can continue managing the contract through:

• centralized contract storage;
• alerts and reminders;
• renewal tracking;
• tracking post-signature obligations, milestones, and deliverables; and
• reporting, custom metrics, and KPIs.

The appropriate electronic or digital signing method, certificate requirements, identity-verification requirements, and legal validity still depend on the selected signing service, transaction, document, and jurisdiction.

With Lexzur CONTRA, signing becomes one connected stage of the contract lifecycle rather than an isolated final step.

Bringing It All Together

Digital signatures can provide stronger assurance around document integrity and the signing process.

In this sense, digital signatures provide a technical foundation, not a complete contract management solution on their own.

But organizations managing contracts at scale also need visibility into what happens before and after execution.

Connecting drafting, review, approvals, signing, storage, renewals, and obligation tracking within a broader contract workflow can reduce manual handoffs and give teams greater control throughout the lifecycle.

Lexzur CONTRA brings those surrounding contract processes together while connecting teams with supported electronic and digital signing services.

Explore What Is Contract Management Software? Complete 2026 Guide to learn more about how signing fits into the wider contract lifecycle.

Bring Your Contract Workflow Into Lexzur CONTRA

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