Everything you need to know about electronic signatures
For all documents that require a signature, the digital equivalent needs a suitable replacement: an electronic signature (also called an e-signature).
Advanced electronic signatures can be compared to a digital seal. This secures digital documents and allows verification of both authenticity (the signature can be linked to a person) and integrity (the document has not been altered later).
Optimize business processes with electronic signatures
Electronic signatures allow many processes to run fully digitally. Companies save time and resources because signers do not need to be physically present and printing is no longer required.
This is especially valuable for workflows with many documents or multiple signers.
Electronic signature vs. digital signature
Note: Since terminology differs by legal jurisdiction and language, this article uses the terms in the common German legal context.
The electronic signature is primarily a legal term and is functionally used like a handwritten signature, for example when signing contracts.
The digital signature is a cryptographic process. An electronic signature is created using a private signing key and can be verified by recipients with the corresponding public key.
The three types of electronic signatures
In practice, three forms are commonly distinguished: SES (Simple Electronic Signature), AES (Advanced Electronic Signature), and QES (Qualified Electronic Signature). They differ in legal strength and typical use cases.
| Criterion | SES - simple electronic signature | AES - advanced electronic signature | QES - qualified electronic signature |
|---|---|---|---|
| Differences | Basic level, for example inserted signature image, stamp, or seal. | Additional technical safeguards; signer is uniquely linked to the signature. | Highest legal and security level; based on a qualified certificate and secure signature creation device. |
| Creation | A digital signature image or stamp is inserted. | Usually created with an advanced certificate for a natural or legal person, issued by a recognized certification authority (CA). | Certificate issued by a state-recognized trust service provider; validity is often additionally verified with a time stamp. |
| Security level | Low; subsequent modifications are comparatively easy. | Manipulation is generally detectable; significantly higher trust level than SES. | Very high; in many scenarios legally equivalent to a handwritten signature under EU rules. |
| Typical use cases | Internal documents, emails, and processes with low legal risk. | Contracts and business documents with medium legal risk, for example B2B processes. | Highly regulated procedures, for example public procurement or specific legal and administrative workflows. |
Legal and regulatory background
The German Federal Office for Information Security (BSI) provides a useful overview of legal and technical basics for electronic signatures:
More information about digital signatures with webPDF:
https://www.webpdf.de/en/pdf-digital-sign-document
More information on signatures and security:
- Signature forms: https://en.wikipedia.org/wiki/Electronic_signature
- Cryptography background: https://en.wikipedia.org/wiki/Digital_signature
- Using signatures with webPDF: https://www.webpdf.de/en/pdf-digital-sign-document