eIDAS: The Electronic Identification, Authentication, and Trust Services Regulation is a legal framework established by the European Union to facilitate cross-border electronic transactions. It aims to ensure the security and legality of digital transactions by setting unified standards and enabling interoperability of electronic signatures, authentication, and trust services.
The eIDAS framework defines three types of electronic signatures:

1. SES (Simple Electronic Signature): Used for basic identity verification;

2. AES (Advanced Electronic Signature): Offers higher security by ensuring the signature is uniquely linked to and verifiable for the signer;

3. QES (Qualified Electronic Signature): The highest level of signature, legally equivalent to a handwritten signature, supported by a qualified certificate issued by a trusted provider.