“Please sign and stamp the attached.” It’s one of the most common lines in business email, and it hides a real confusion. Some people paste a PNG of their company stamp and a scanned signature, then send the file back. Others reach for a certificate-based digital signature. Both say they’ve “signed” the document. Legally and technically, they’ve done very different things.
This guide explains the difference between a digital signature, an electronic seal, and a visual digital stamp, where each one carries legal weight, and how to combine them so your documents look right and hold up if they’re ever challenged.
Disclaimer: This is a practical overview, not legal advice. Signature and seal laws differ by country, industry, and document type. Check with counsel or your regulator for anything high-stakes.
Visual Stamps vs Cryptographic Signatures: The Core Confusion
The confusion comes from one word doing two jobs. “Digital” can mean a picture on a screen or mathematics that proves something.
- A digital stamp (or digital seal image) is a visual mark: a PNG, SVG, or PDF overlay of a company stamp, notary-style seal, or status stamp like APPROVED or PAID. It tells a human reader who is acting or what state the document is in.
- A digital signature is a cryptographic operation. It doesn’t have to look like anything at all. It binds a document to a certificate holder and makes any later change detectable.
A useful way to remember it: a stamp is something you see; a digital signature is something you verify.
| Visual digital stamp | PKI digital signature | |
|---|---|---|
| What it is | An image placed on the page | A hash of the document encrypted with a private key |
| Proves identity? | No. Anyone with the file can copy it. | Yes, through a certificate issued to the signer |
| Detects tampering? | No | Yes. Any change breaks or flags the signature. |
| Needs a certificate? | No | Yes |
| Visible on the page? | Always | Optional (can be invisible) |
| Typical use | Invoices, approvals, receipts, branding, status | Contracts, filings, tenders, regulated records |
What Is a Digital Signature? (PKI, Hashes, Certificates)
A digital signature uses public key infrastructure (PKI). In plain terms:
- The document is hashed. Software runs the file through a hash function (such as SHA-256), producing a short fingerprint. Change a single character and the fingerprint changes completely.
- The hash is encrypted with the signer’s private key. Only the signer holds that key, usually on a smart card, USB token, HSM, or a cloud signing service.
- The certificate travels with the signature. It contains the signer’s public key and identity, and it’s issued by a certificate authority (CA) that has verified who they are.
- Anyone can verify it. A PDF reader decrypts the signature with the public key, re-hashes the document, and compares. If the hashes match and the certificate chains to a trusted CA, the signature is valid.
In PDFs, signatures follow standards such as PAdES (PDF Advanced Electronic Signatures), and good implementations add a trusted timestamp so the signature can still be validated after the certificate expires.
What a digital signature gives you, and a stamp image doesn’t:
- Authenticity: who signed it
- Integrity: the document hasn’t changed since signing
- Non-repudiation: the signer can’t credibly deny signing
What Is a Digital Stamp / Electronic Seal?
This is where the terms overlap, so it helps to split them.
1. The visual digital stamp. A designed image of your stamp or seal, the kind you make in our Stamp Studio. It reproduces the look and function of a rubber stamp on electronic documents: company name, registration number, status word, date. It’s a representation, not proof.
2. The electronic seal (eIDAS sense). In EU law, an electronic seal is a cryptographic mechanism, technically similar to a digital signature, but issued to a legal person (a company, public body, or organisation) rather than an individual. It proves a document came from that organisation and hasn’t been altered. Banks use them on statements, tax authorities on notices, and businesses on bulk e-invoices.
So “digital seal” can mean either a nice-looking PNG or a certificate-backed cryptographic seal. When someone asks for a “digital seal”, it’s worth asking which one they mean. A regulator or counterparty asking for an electronic seal almost always means the cryptographic kind.
Individual Identity (Signatures) vs Entity Action (Seals)
The most useful mental model is who is acting:
| Tool | Represents | Paper equivalent |
|---|---|---|
| Signature (handwritten, electronic, or digital) | A person: their intent and consent | A wet-ink signature |
| Electronic seal (cryptographic) | An organisation: the origin and integrity of its document | An embossed corporate seal or official chop |
| Visual stamp | An organisation or a status, visually | A rubber stamp impression |
That’s why a typical company document carries both: a director signs as an individual, and the company stamps or seals to show the act is on its behalf. Our company stamp format guide covers what that stamp should contain, and the LLC corporate seal vs rubber stamp guide explains when a physical seal still matters.
Legal Frameworks: US ESIGN/UETA vs EU eIDAS
United States: ESIGN and UETA
The US takes a technology-neutral approach. The federal ESIGN Act (2000) and the Uniform Electronic Transactions Act (UETA), adopted by 49 states (New York has its own equivalent law), say an electronic signature can’t be denied legal effect just because it’s electronic.
An “electronic signature” under US law is broad: a typed name, a click on “I agree”, a scanned signature, or a PKI digital signature can all qualify, if the person intended to sign and the record is kept properly. What differs is evidence: if a signature is disputed, a certificate-based signature with an audit trail is far easier to defend than a pasted image.
US law has no general concept of an “electronic seal” for companies. Specific exceptions exist: notaries follow state rules for electronic notarization (see our digital notary seal requirements guide), and some agencies and courts set their own filing rules.
European Union: eIDAS (Simple, Advanced, Qualified)
The eIDAS Regulation (EU) No 910/2014, updated by eIDAS 2.0 (Regulation (EU) 2024/1183), defines three levels for both signatures and seals:
| Level | Signature (natural person) | Seal (legal person) | Legal weight |
|---|---|---|---|
| Simple | Any electronic data used to sign: typed name, image, click | Any electronic data attached to show origin | Admissible as evidence; can’t be rejected just for being electronic |
| Advanced (AdES) | Uniquely linked to the signer, under their sole control, detects changes | Same requirements, linked to the organisation | Stronger evidence; widely used in business |
| Qualified (QES / QSeal) | Advanced + qualified certificate + qualified signature device | Advanced + qualified certificate + qualified seal device | QES = handwritten signature across the EU. QSeal is presumed to guarantee integrity and origin. |
A pasted stamp image sits at the “simple” level at most. It’s admissible, but carries little weight on its own if challenged.
The UK keeps a similar framework under UK eIDAS and the Electronic Communications Act 2000. Many other countries follow comparable models. India’s IT Act, 2000 recognises PKI digital signatures from licensed CAs (DSCs) and Aadhaar-based eSign, for example.
The Ideal Workflow: Visual Stamp + Cryptographic Signature
You rarely have to choose. The strongest documents use both: a visual stamp for human readers, and a cryptographic signature or seal for proof.
The rule: stamp first, sign last.
- Finalise the content. No more edits after this point.
- Add the visual stamp. Place your company stamp, seal, or status stamp (APPROVED, PAID, CERTIFIED TRUE COPY) with the PDF & Word Stamper. It runs entirely in your browser, so the file is never uploaded.
- Apply the digital signature or seal last. Use Adobe Acrobat, your national eID tool, a DSC token, or a signing platform. This locks the document, stamp included.
- Send the signed file without re-saving it through other tools. Even “harmless” re-saves can alter the bytes.
Why the order matters: our stamper (like most browser PDF tools) writes a fresh copy of the file, which breaks any signature already on it. Tools that save incrementally keep the original signed revision intact, but the validator will still report “document modified after signing”, and certified PDFs set to allow no changes will show the signature as invalid. Our guide to stamping and signing PDFs in your browser walks through the full sequence.
Pro Tip: Many signing tools let you choose the appearance of a visible signature, including a custom image. Exporting your stamp as a transparent PNG or PDF and using it as the signature appearance gives you one mark that looks like your stamp and carries the cryptographic proof.
When a Visual Stamp Alone Is Enough
For a large share of everyday business paperwork, nobody expects a certificate. A clean, consistent visual stamp is the norm:
- Invoices, quotations, and delivery notes, especially in markets where a company stamp is customary
- Internal approvals and status marks: APPROVED, PAID, RECEIVED, POSTED, VERIFIED
- Receipts and acknowledgements for goods or documents
- Branding and presentation: letterheads, certificates of participation, packing slips
- Copies and drafts: COPY, DRAFT, CONFIDENTIAL watermarks
Add a cryptographic signature or seal when:
- A law, regulator, or tender explicitly requires a digital signature, DSC, QES, or QSeal
- The document is a contract or carries significant money, liability, or IP
- The file will be relied on by third parties who need to verify it independently (bank statements, certificates, audit reports)
- E-invoicing rules in your country require signed or sealed invoices
- You expect the document might be disputed later
Design the Visual Half of the Workflow
The cryptographic signature comes from your CA or signing platform. The visual stamp you can make yourself, free:
- Open the Stamp Studio or pick a ready-made business stamp template.
- Enter exact legal details: registered company name, registration number, and tax ID if your counterparties check it.
- Keep it legible at small sizes. A 38–42 mm round seal or a 58 × 22 mm rectangle works well on A4 and Letter pages.
- Export a transparent PNG for PDFs and Word, or SVG if you also want a physical stamp made from the same design.
- Stamp, then sign. Place the stamp with the PDF & Word Stamper, then apply your digital signature as the final step.
Final Thoughts
A digital stamp shows who is acting or what state a document is in. A digital signature or electronic seal proves it. Under US law, both can count as electronic signatures, but only the cryptographic one gives you strong evidence. Under eIDAS, the levels are explicit, and only qualified signatures and seals carry the highest legal presumptions.
Use a visual stamp for the everyday, add cryptography where it’s required or where the stakes are high, and always stamp first, sign last.
Create Your Digital Stamp
👉 Launch the Free Stamp Studio: design a company stamp, round seal, or status stamp in minutes. 100% free, no watermarks, SVG and high-res transparent PNG export.
Then place it on any PDF or Word file with the PDF & Word Stamper, processed entirely in your browser.