What is the difference between an electronic and a digital signature?

An electronic signature is a legal term; a digital signature is a technical one. The eIDAS Regulation recognises only the electronic signature and defines its legal effect. A digital signature refers to the cryptographic method — asymmetric encryption using a key pair and a hash value — used to create advanced and qualified signatures.

In everyday use the terms are treated as synonyms, which is legally imprecise. Every digital signature is an electronic signature, but not every electronic signature is digital: a photographed signature image pasted into a PDF is legally a simple electronic signature, yet technically not a digital signature, because neither a certificate nor a key pair is involved.

Here's how the two terms differ in practice:

• Legal layer: The electronic signature describes what legal effect a declaration in electronic form carries — set out in Articles 25 to 34 of the eIDAS Regulation.
• Technical layer: The digital signature describes the method: hash generation, encryption with the private key and verification with the public key.
• Certificate dependency: Digital signatures always require a certificate. Simple electronic signatures work without one and are correspondingly weaker as evidence.
• Evidential weight: Only certificate-based methods prove authenticity and integrity technically. With a signature image, the relying party must prove attribution itself.
• Verifiability: Digital signatures are checked automatically by every common PDF reader; in Adobe Acrobat Reader this appears as a green tick.
• Wording in contracts: Tenders should state the required eIDAS level — SES, AES or QES — rather than the imprecise phrase "digital signature".

The cryptography behind it:

• Key pair: Each user holds a secret private key and a freely distributable public key. No shared secret between the parties is required.
• Hash value: A unique fingerprint is calculated from the document. Even a minimal change produces a completely different hash.
• Encryption and verification: The signatory encrypts the hash with the private key; the recipient decrypts it with the public key and compares it against the hash they compute.

primesign produces digital signatures in the technical sense — certificate-based, cryptographically verifiable and stored in PAdES format — while assigning each one unambiguously to an eIDAS signature level. That means every document carries a documented legal effect, rather than relying on a vague claim about "digital signatures".