Understanding digital signatures: AES, QES, SES

Exploring different types of digital signatures.

---

Digital signatures play a crucial role in modern document authentication, ensuring security and integrity in various online transactions. Among the various types of digital signatures, advanced electronic signatures (AES), qualified electronic signatures (QES) and standard electronic signatures (SES) are the most prominent. Each type serves distinct purposes and meets different levels of security and regulatory requirements.

Here’s an in-depth look at AES, QES and SES digital signatures and their applications:

AES provides a robust solution for securing digital documents. AES is designed to ensure the signer's identity, document integrity and the detection of any post-signing alterations.

AES employs cryptographic algorithms to create a unique digital fingerprint, or hash, of the signed document. This hash is encrypted with the signer's private key, forming the digital signature. The document and its digital signature can be verified using the public key, confirming authenticity and integrity.

Key features and benefits

• Security: AES uses strong encryption to protect documents.
• Non-repudiation: Signers cannot deny their involvement, enhancing legal accountability.
• Compliance: Meets stringent regulations, such as eIDAS in the EU.
• Efficiency: Streamlines digital document signing, reducing paperwork and enhancing productivity.

Applications

• Contracts and agreements: Widely used for legal, financial and business transactions.
• Regulatory compliance: Essential in industries like healthcare and finance.
• Remote transactions: Facilitates secure electronic signing from any location.

QES represents the highest level of digital signature assurance, offering strong legal validity and regulatory compliance.

QES adheres to specific regulations, such as eIDAS in the EU, ensuring it meets the highest standards of legal certainty. It is considered equivalent to handwritten signatures, making it suitable for contracts and other binding documents.

Requirements for qualification

• Qualified certificate: Issued by a trusted certification authority (CA).
• Secure signature creation devices (SSCDs): Securely generate and store private keys.
• Regulatory compliance: Adheres to technical and cryptographic standards.

Legal validity and compliance

QES provides a presumption of authenticity and integrity under regulations like eIDAS, making it indispensable for regulated environments.

Applications

• Banking and finance: Used in financial transactions and client onboarding.
• Healthcare: Facilitates secure electronic exchange of patient records and medical documents.

SES is the most basic form of digital signature, designed for everyday transactions without requiring advanced cryptographic measures.

SES includes methods such as typed signatures or "I agree" checkboxes. It is easy to use and widely adopted across various digital platforms.

SES does not offer the same level of security or legal validity as AES and QES. While suitable for informal agreements, it may not be appropriate for documents requiring high levels of legal assurance.

Use cases where SES is appropriate:

• Online forms: Common for user agreements and consent forms on websites.
• Internal documents: Used for memos and approvals within organisations.
• Informal agreements: Suitable for casual business transactions and personal agreements.

Advantages and limitations

• Advantages: Offers convenience and accessibility, eliminating the need for physical paperwork.
• Limitations: Lacks advanced security features and may not provide sufficient legal validity for formal agreements.

Digital signatures have revolutionised document authentication, offering varied solutions for different needs. Understanding the distinctions between AES, QES and SES is crucial for selecting the appropriate type of signature based on security, legal requirements and the nature of the transaction.

Whether you need the robust security of AES, the legal certainty of QES or the simplicity of SES, these digital signatures continue to enhance the way we conduct business and manage documents in the digital age.

Contact SigniFlow to learn more.