Digital Signatures vs Electronic Signatures: What's the Difference?

The Confusion Between Digital and Electronic Signatures

The terms "digital signature" and "electronic signature" are frequently used interchangeably, but they refer to two distinctly different things. Understanding the difference is important because it affects the legal validity, security level, and appropriate use case for each type. Choosing the wrong type of signature for a given situation can create legal vulnerability or unnecessary complexity.

In simple terms: all digital signatures are electronic signatures, but not all electronic signatures are digital signatures. An electronic signature is the broader category, while a digital signature is a specific, more secure type within that category.

What Is an Electronic Signature?

An electronic signature (or e-signature) is any electronic indication of intent to agree to or approve the contents of a document. It is the broadest category and includes:

• Drawn signatures: A signature drawn on a touchscreen or with a mouse, like what you create with the Sign PDF tool
• Typed names: Your name typed in a signature field or in a distinctive font
• Uploaded images: A scanned or photographed image of your handwritten signature
• Click-to-sign: Clicking an "I agree" button or checkbox
• Email signatures: Your name and title at the end of an email confirming agreement

The common thread is that all of these demonstrate the signer's intent to agree. They do not inherently include cryptographic verification or tamper-evident technology, though they are still legally valid for most transactions.

What Is a Digital Signature?

A digital signature is a specific type of electronic signature that uses cryptographic technology to provide additional security guarantees. It relies on a public key infrastructure (PKI) and digital certificates issued by trusted Certificate Authorities (CAs). When you apply a digital signature to a PDF:

1. A mathematical hash of the document content is created
2. This hash is encrypted with your private key (which only you possess)
3. The encrypted hash is embedded in the document along with your digital certificate
4. Anyone can verify the signature using your public key

This process provides three guarantees that simple electronic signatures cannot:

• Authentication: The signature proves the identity of the signer through a certificate chain back to a trusted authority
• Integrity: Any modification to the document after signing invalidates the signature, proving the document has not been tampered with
• Non-repudiation: The signer cannot deny having signed the document, because only their private key could have created the signature

Side-by-Side Comparison

When to Use Each Type

Electronic Signatures Are Sufficient For:

• Business contracts and service agreements
• Employee onboarding documents
• Client approval forms
• Internal company memos and acknowledgments
• Sales quotes and purchase orders
• Rental and lease agreements
• Permission slips and consent forms

Digital Signatures Are Recommended For:

• Government and regulatory filings
• High-value financial transactions
• Healthcare and pharmaceutical documents
• Legal documents requiring non-repudiation
• International trade and customs documents
• Software distribution and code signing
• Situations where document tampering must be detectable

How to Add an Electronic Signature to a PDF

Adding an electronic signature to a PDF is straightforward with the Sign PDF tool:

If you also need to fill in other information (name, date, address), use the Fill PDF tool to complete all fields before or after signing.

Strengthening Your Electronic Signature

While a basic electronic signature is legally sufficient for most purposes, you can strengthen its evidential value with these practices:

• Add a date and timestamp: Including the date and time of signing provides a clear record of when the agreement was made.
• Use email confirmation: Sending the signed document from your verified email address creates an additional record linking you to the signature.
• Keep an audit trail: Save copies of the unsigned and signed versions, along with any correspondence related to the signing.
• Flatten the PDF after signing: Use the Flatten PDF tool to permanently embed the signature, preventing it from being moved or removed.
• Password protect the signed document: Use the Protect PDF tool to prevent unauthorized modifications after signing.

Frequently Asked Questions