Electronic signature vs digital signature: what's the difference?

People often use "electronic signature" and "digital signature" as if they meant the same thing. They are related, but they answer different questions. One is about the law: did this person agree to this document? The other is about technology: has this file changed, and which certificate vouches for it?

What is an electronic signature?#

An electronic signature is a legal concept. Broadly, it is any electronic sound, symbol or process that a person attaches to a record, or associates with it, with the intention of signing it. A typed name at the end of an email, a signature drawn with a finger on a phone and a click on an "I agree" button can all qualify, depending on the context and the law where you are.

What matters is less the look of the signature than the facts around it. Courts and regulators commonly look for:

• Intent to sign: the person took a deliberate action to sign.
• Consent to deal electronically: the people involved agreed to do it this way.
• Association with the record: the signature is clearly linked to the specific document.
• Attribution and retention: you can show who signed and when, and keep an accurate copy.

Many countries have electronic transactions laws saying that a signature can't be denied legal effect just because it is electronic. The details and the exceptions differ from place to place, so check our e-signature legality guide for your country.

What is a digital signature?#

A digital signature is a cryptographic technique. It uses a pair of mathematically linked keys: a private key that only the signer (or a signing service) holds, and a public key that anyone can use to check the result. Software calculates a unique fingerprint of the file (a hash) and signs it with the private key. Anyone with the public key can then confirm that the signature matches and that the file hasn't changed since. Alter a single character and the check fails.

To tie a public key to a real person or organisation, digital signatures rely on certificates issued by certificate authorities, a system known as public key infrastructure (PKI). The certificate is what lets software say "signed by X, and not modified since."

How the two relate#

The simplest way to think about it: electronic signature is the legal category, and a digital signature is one way to implement it. A digital signature can be used to create an electronic signature, but plenty of everyday electronic signatures involve no personal certificate at all.

Digital signatures are also used for things that aren't a person's signature. A platform can digitally seal a finished document with its own certificate to show the file is intact, while the people in it signed with simple electronic signatures. That is how Signkoi works.

Terms you'll meet around the world#

Legal systems often sort electronic signatures into levels. The best known is the EU's eIDAS regulation, which defines three:

• Simple electronic signature (SES): data in electronic form that the signer uses to sign, such as a typed or drawn signature submitted through a secure link. It's the most common type for everyday agreements, and its weight as evidence depends on the surrounding facts and records.
• Advanced electronic signature (AdES): uniquely linked to and capable of identifying the signer, created with data under the signer's sole control, and linked to the document so that any later change can be detected. This usually involves certificate-based cryptography.
• Qualified electronic signature (QES): an advanced signature created with a qualified signature creation device and backed by a qualified certificate from a trust service provider. In the EU it has the same legal effect as a handwritten signature.

Elsewhere you'll meet similar ideas under other names. Some countries give special weight to certificate-based signatures from licensed or accredited providers, such as digital signature certificates in India, ICP-Brasil certificates in Brazil or qualified enhanced signatures in Russia. There, a simple e-signature can often still evidence an agreement, but some documents and official filings may require the certificate-based kind.

Signing with Signkoi creates a simple electronic signature. Signkoi doesn't offer advanced or qualified signatures based on a personal certificate.

Comparison at a glance#

What a tamper-evident seal and trusted timestamp do#

When every recipient has finished, Signkoi completes the document in a few steps:

1. Signatures and fields are embedded in the PDF exactly where you placed them.
2. A tamper-evident seal, a digital signature applied by the platform, is added to the finished PDF. If anyone edits the file afterwards, the seal no longer validates, so the change can be detected.
3. A trusted timestamp records when the document was sealed, so the completion time can be checked later.
4. An audit trail and certificate of completion summarise who did what and when, such as sending, opening and signing, with times, IP addresses and browser details.

The seal doesn't turn a simple signature into a qualified one. It protects the integrity of the record, which often matters most if a signature is ever questioned.

Checking a document at /verify#

Anyone who holds a signed Signkoi PDF (you, your counterparty or an auditor) can upload it at signkoi.com/verify to check that it's authentic and unchanged since it was signed. No account is needed.

When you might need a stronger signature type#

Simple electronic signatures backed by good records are widely used for everyday business documents such as NDAs, sales agreements, offer letters and internal approvals. Some situations call for more:

• The law requires "written form" and, where you are, accepts only a qualified electronic signature in its place.
• A government body, court, registry or regulator asks for a specific certificate-based signature.
• The document is high-value or regulated, or it's one of those that often still need wet ink or a notary, such as wills, many real-estate deeds and powers of attorney.
• Your counterparty's own policy requires an advanced or qualified signature.

If any of these apply, or you aren't sure, ask a lawyer where you are. Signkoi lets you add identity checks, such as an access code or a one-time code sent by email, but if a document needs a higher legal level, use a provider and process designed for it.

FAQ#

Is a digital signature more legally valid than an electronic signature?#

Not automatically. A digital signature is a technique, not a legal status. What counts is whether the signature meets the requirements of the law that applies. In the EU, for example, only a qualified signature automatically equals a handwritten one, but no electronic signature can be refused as evidence just because it's electronic.

Is a Signkoi signature a digital signature?#

Signers create simple electronic signatures. Signkoi then seals the completed PDF with a digital signature and adds a trusted timestamp, so anyone, with or without an account, can check its integrity at signkoi.com/verify.

Which type should I use for an NDA?#

Many businesses use simple e-signatures for NDAs. Our guide to sending an NDA for signature walks through it step by step. If your situation is unusual, check with a lawyer first.

Want to see how it works in practice? Create a free account or explore all Signkoi features.