Digital vs Electronic Signature: What's the Difference?
Published by PDFToolz · Updated · Technical references listed below
An electronic signature is any electronic mark a person uses to sign, such as a typed name or a drawn signature. A digital signature is one specific kind that uses cryptography to prove who signed and that nothing changed afterwards. People mix up the terms, which can lead to an overbuilt process for a simple approval, or too little protection on a document that regulators expect to be tamper-evident.
This guide defines each term, explains the technical and legal differences, shows how a digital signature works inside a PDF and maps which type to use under the US ESIGN Act and the EU eIDAS regulation.
What is an electronic signature?
Under the US ESIGN Act, an electronic signature is any electronic sound, symbol or process attached to or logically associated with a record and adopted by a person with the intent to sign. The definition is broad on purpose. What makes something a signature is the signer's intent to be bound, not the technology.
Because the test is intent, electronic signatures take many everyday forms. They are quick to use and legally valid for most business transactions in the US and EU.
- A name typed into a signature block
- A signature drawn with a mouse, stylus or finger
- An uploaded image of an ink signature
- A click on an I Agree or Accept button
- An email reply that confirms agreement
- A PIN or one-time code entered to approve
What is a digital signature?
A digital signature is a type of electronic signature built on cryptography. It uses Public Key Infrastructure (PKI). The signer holds a private key that only they control, paired with a public key that anyone can use to check the signature. A trusted Certificate Authority (CA) issues a certificate that ties the key pair to a verified identity.
When you sign, the software calculates a hash of the document and signs that hash with your private key. Only that key can produce this result. The signature and your certificate are embedded in the file. Anyone can later recalculate the hash and check it against the signature with your public key.
This gives three guarantees a basic electronic signature can't give on its own. Authentication means a CA has verified the signer's identity. Integrity means any change to the signed content breaks the hash and invalidates the signature. Non-repudiation means only the private key holder could have signed, so they can't credibly deny it.
The difference at a glance
Every digital signature is an electronic signature, but not every electronic signature is a digital signature. Electronic signature is the legal umbrella. Digital signature is one high-assurance technology under it.
The practical gap is evidence. A typed name shows intent but proves little about identity or tampering, so it relies on the signing platform's audit trail. A digital signature carries cryptographic proof of identity and integrity inside the document.
- An electronic signature rests on intent to sign. A digital signature rests on PKI and certificates.
- An electronic signature proves identity through the platform's audit trail. A digital signature uses a certificate verified by a CA.
- An electronic signature can't detect edits by itself. A digital signature breaks if anything changes.
- An electronic signature's proof stays with the service. A digital signature's proof is embedded in the file.
- Electronic signatures suit everyday agreements. Digital signatures suit regulated, high-value documents.
Signature laws: ESIGN, UETA and eIDAS
In the US, the federal ESIGN Act (2000) and the state-level UETA (1999) give electronic signatures the same legal weight as handwritten ones. The conditions are intent to sign, consent to do business electronically, a clear link between signature and record, and proper record keeping. US law is technology-neutral and doesn't require a digital (PKI) signature.
The EU uses tiers under eIDAS (Regulation 910/2014). It defines three levels of assurance, and the level you need depends on the risk of the transaction and any sector rules.
- A simple electronic signature (SES) is any basic electronic form, such as a typed name or a click.
- An advanced electronic signature (AdES) is uniquely linked to the signer, can identify them, is created with signature data under their sole control and shows any later change (eIDAS Article 26). In practice this needs digital signature technology.
- A qualified electronic signature (QES) is an AdES made with a qualified signature creation device and a qualified certificate from a qualified trust service provider. Under Article 25(2), only a QES has the same legal effect as a handwritten signature in every EU member state.
How a digital signature works in a PDF
PDF is the most common container for digital signatures. Signing is defined in ISO 32000, and for eIDAS the PAdES (PDF Advanced Electronic Signatures) profile is defined by ETSI in EN 319 142. The signature sits in a signature field in the document.
When signing, the software hashes a set byte range of the file, often with SHA-256, signs the hash with the private key and embeds the signed hash and the signer's certificate. A trusted timestamp from a Time Stamping Authority (RFC 3161) records when signing happened, independent of the signer's own clock.
A reader checks it in reverse. It recalculates the hash to confirm nothing changed, checks that the certificate chains to a trusted root, and uses CRL or OCSP data to check the certificate wasn't revoked. Long-Term Validation (LTV) embeds the revocation and timestamp data in the PDF, so the signature can still be checked years later, after the certificate expires.
When to use each
Match the signature to the document's risk, the rules that apply and how long you need to prove it hasn't changed. For most everyday business, an electronic signature with a good audit trail is legally enough and much simpler.
Use a digital signature when identity, tamper evidence or long-term proof matter, or when a law or the other party requires an advanced or qualified signature. PDFToolz eSign PDF adds an electronic signature image to the page. It does not create a certificate-based digital signature.
- Electronic signatures fit internal approvals, NDAs, sales contracts, consent and HR forms, and most B2B agreements.
- Digital signatures fit financial and legal filings, government and public tender submissions, cross-border EU documents that need AdES or QES, and records that must stay verifiable for years.
- In the EU, check whether the transaction needs a QES. Some acts, such as certain notarial or real estate documents, require it by law.
Key takeaways
- ✓Every digital signature is an electronic signature, but not every electronic signature is a digital signature.
- ✓An electronic signature shows intent to sign. A digital signature uses PKI, certificates and hashing to prove identity and detect changes.
- ✓US law (ESIGN and UETA) is technology-neutral and accepts electronic signatures without PKI.
- ✓EU eIDAS has three tiers, simple, advanced and qualified. Only a qualified signature equals a handwritten one in every EU country.
- ✓A PDF digital signature embeds a hashed byte range, a CA-issued certificate and often a trusted timestamp, so it can be checked later.
Tools for the job
Frequently asked questions
What is the difference between a digital and an electronic signature?
An electronic signature is any electronic mark made with intent to sign, such as a typed name, a drawn signature or a click. A digital signature is a type of electronic signature that uses a certificate and cryptography to prove who signed and to show if the document changed afterwards.
Is an electronic signature legally binding?
Yes. Under the US ESIGN Act and UETA, and the EU eIDAS regulation, electronic signatures are binding when there is intent to sign, consent to do business electronically, and the signature is linked to and kept with the record. A typed name or click can form a valid contract for most business deals, though some documents, such as wills or certain notarial deeds, may be excluded by law.
Is a digital signature more secure than an electronic signature?
For proving identity and detecting changes, yes. A digital signature uses cryptographic hashing and a certificate from a trusted Certificate Authority, so any change after signing shows up and the signer's identity is verified. A basic electronic signature, such as a typed name, relies on the platform's audit trail instead of cryptography inside the file.
What is the difference between eIDAS advanced and qualified signatures?
An advanced electronic signature (AdES) meets the four requirements of eIDAS Article 26. It is uniquely linked to the signer, can identify them, is created with signature data under their sole control and shows any later change. A qualified electronic signature (QES) is an AdES made with a qualified signature creation device and a qualified certificate from a qualified trust service provider. Under Article 25(2), only a QES equals a handwritten signature in every EU member state.
Do I need a digital signature or is an electronic one enough?
For most agreements, such as NDAs, sales contracts, internal approvals and consent forms, an electronic signature with a good audit trail is legally enough and much simpler. Use a digital signature when you need verified identity, tamper evidence or long-term proof, or when a regulation or the other party requires an advanced or qualified signature.
How is a PDF digital signature checked?
The reader recalculates the document's hash and compares it to the signed hash to confirm nothing changed. It checks that the signer's certificate chains to a trusted root and uses CRL or OCSP data to confirm it wasn't revoked. A trusted timestamp and Long-Term Validation (LTV) data keep the signature verifiable after the certificate expires.
What does non-repudiation mean for signatures?
It means a signer can't credibly deny signing a document. Digital signatures provide it because only the holder of the private key could have made the signature, and any change breaks the hash. Basic electronic signatures give weaker non-repudiation through audit logs and captured metadata.
Related terms
Sources and further reading
- eSignature FAQ from European Commission
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