
Guide to Advanced Electronic Signatures (AES)
Find out everything you need to know about Advanced Electronic Signatures and the high levels of security they provide.
- Key Takeaways
- Advanced Electronic Signature definition (AES)
- Why and when to use an Advanced Electronic Signature – requirements
- Qualified vs Advanced Electronic Signature: key differences
- Advanced Electronic Signature requirements in the UK
- How to create an Advanced Electronic Signature online
- FAQs about Advanced Electronic Signatures
Table of contents
- Key Takeaways
- Advanced Electronic Signature definition (AES)
- Why and when to use an Advanced Electronic Signature – requirements
- Qualified vs Advanced Electronic Signature: key differences
- Advanced Electronic Signature requirements in the UK
- How to create an Advanced Electronic Signature online
- FAQs about Advanced Electronic Signatures

Key Takeaways
What is it? An AES provides enhanced security by uniquely linking the signature to the signer.
When to use it? Use an AES for high-risk / value contracts, secure documents, and when regulations require a higher level of identity verification.
What makes it "advanced"? It must meet four criteria under eIDAS regulations: unique linkage to the signer, clear identification, sole control by the signer, and a way to detect any changes to the document after signing.
AES vs. QES: While AES provides enhanced security, a Qualified Electronic Signature (QES) offers the highest level of legal assurance and is legally equivalent to a handwritten signature.
Advanced Electronic Signatures (AES) provide enhanced security and verification beyond basic electronic signatures, ensuring document integrity and signer authenticity.
This comprehensive guide explains how AES works under UK & EU eIDAS regulations, when to use this higher level of verification, and how Docusign solutions help organisations meet compliance requirements for high-value transactions and legally sensitive agreements.
Every day, companies are switching to electronic signatures to speed up their approval and validation processes. A question that comes up regularly: what is an advanced signature? And what additional security does it provide compared to a Simple Electronic Signature (SES)? This article explains everything you need to know about Advanced Electronic Signatures (AES).
Advanced Electronic Signature definition (AES)
An Advanced Electronic Signature (AES) represents a higher security level in the electronic signature hierarchy, sitting between simple electronic signatures (SES) and Qualified Electronic Signatures (QES). AES provides enhanced authentication and security features that make it suitable for higher-value transactions and contracts.
Key criteria under eIDAS Article 26
According to Article 26 of the eIDAS regulation, which has been adopted in both the EU and UK, an Advanced Electronic Signature must fulfil four essential requirements:
Unique link to signatory: The signature must be uniquely connected to the person signing, typically through a private key that belongs only to them.
Signatory identification: The signature must enable clear identification of the signer through robust verification methods.
Sole control: The signature must be created using electronic signature creation data that the signatory can maintain under their exclusive control with a high level of confidence.
Data integrity protection: The signature must be linked to the signed data in a way that any subsequent modification is detectable, ensuring document integrity throughout its lifecycle.
Simple vs Advanced vs Qualified: quick comparison
Type | Security Level | Typical Use | Verification Method |
SES | Basic | Everyday agreements, internal documents | Email, password |
AES | Enhanced | High-value transactions, secure documents | ID verification, digital certificates |
QES | Highest | Highly regulated transactions, legal equivalence to handwritten signatures | Face-to-face verification, qualified certificates |
Importantly, under eIDAS Article 25(1), an Advanced Electronic Signature "shall not be denied legal effect and admissibility as evidence in legal proceedings" solely because it is in electronic form, making AES a legally robust option for most business transactions.
Why and when to use an Advanced Electronic Signature – requirements
An Advanced Electronic Signature adds essential security measures beyond a simple e-signature, providing higher levels of signer identity verification and anti-fraud sealing to protect against unauthorised access. This type of electronic signature unequivocally links to the signatory's identity, ensuring a higher level of security for your agreements.
AES is particularly valuable for higher-risk contracts such as consumer credit, secure documents and high-value transactions. Organisations often opt for advanced electronic signatures when dealing with contracts carrying significant risk, or when needing to conform to legal or regulatory requirements.
Advanced Electronic Signature: how does it work?
The main requirement of Advanced Electronic Signatures is enhanced signatory identification. Docusign offers two approaches:
Signatory identification supported by Docusign: The organisation asks Docusign to provide identity verification and advanced certificates. Docusign verifies identity documents sent by signatories, offering maximum security and compliance through a digital certificate that links the signature to the verified ID using robust electronic identification methods. Not only is Docusign a Qualified Trust Service Provider (QTSP) in Europe, but Onfido (our integrated partner carrying out the identity verification) is also a certified Identity Provider (IdP).
Identification delegated to the issuing company: Identity verification is carried out by the issuing company through their preferred methods. The company must ensure good KYC (Know Your Customer) practices, with Docusign confirming the signer's identity via a one-time password sent by SMS.
How does Docusign verify the identity of a signer?
Docusign ID Verification is a digital solution that can verify official identity documents in minutes, and perform real-time biometric checks to confirm a signer is physically present at the time of signature. This digitalisation makes verification possible when face-to-face methods aren't practical, helping organisations speed up their contract processes while protecting sensitive information.
The solution analyses identity documents for various security elements, including validity dates, name matching, machine-readable zones, security features, and signs of tampering. With ID Verification, you protect both your company and the people identified by ensuring only authorised personnel can access contracts.
Qualified vs Advanced Electronic Signature: key differences
Verification steps and legal standing
When selecting between electronic signature solutions, understanding the distinction between Advanced Electronic Signatures (AES) and Qualified Electronic Signatures (QES) is crucial for your organisation. While AES provides enhanced security through identity verification, QES offers the highest level of legal assurance.
A Qualified Electronic Signature (QES) requires face-to-face or equivalent identity verification and is issued by a qualified trust service provider (QTSP). Unlike AES, a QES is legally equivalent to a handwritten signature across the EU and UK, making it the only signature type that doesn't require additional evidence in court proceedings.
When to choose QES over AES
The decision between AES and QES often depends on your organisation's risk assessment and regulatory requirements. QES is the preferred choice when maximum legal weight is essential, when handling highly regulated transactions, or performing cross-border transactions. For example, many organisations implement QES for agreements with multiple parties in different locations, particularly when the stakes are high.
Industries that typically require Qualified Electronic Signatures include:
Financial services for loan agreements and high-value transactions
Healthcare for sensitive medical documentation and compliance
Government and military for official documents requiring maximum security
While AES serves well for most high-value business contracts, QES provides the ultimate assurance for your most critical agreements. As electronic signature adoption continues to grow, understanding when to elevate from AES to QES has become an essential consideration for organisations seeking to balance security, compliance and operational efficiency.
Furthermore, through innovations such as Docusign Identity Wallet, signers can store proof of their verified identity, streamlining the verification process for subsequent digital signature agreements.
Advanced Electronic Signature requirements in the UK
UK regulatory landscape
In the UK, Advanced Electronic Signatures must comply with Article 26 of the eIDAS regulation, which has been adopted into UK law following Brexit. The UK Information Commissioner’s Office (ICO) provides guidance for organisations implementing AES, requiring that signatures be uniquely linked to the signatory, enable clear identification, remain under the signatory's exclusive control, and detect any subsequent change to the signed document.
UK organisations must ensure their electronic signature solutions meet these technical requirements, particularly for high-value transactions and secure documents where simple electronic signatures may not provide sufficient security.
How to create an Advanced Electronic Signature online
Step-by-step with Docusign eSignature
Set up your document by uploading it to the Docusign eSignature platform.
Configure identity verification on the envelope by selecting from options such as ‘Docusign ID Verification with EU Advanced’.
Add recipient information.
Place signature fields and any additional form fields on your document.
Send the document for signing, prompting recipients to verify their identity before completing the electronic signature process.
For customers using the Docusign Intelligent Agreement Management (IAM) platform, you can now require participants to complete the necessary identity verification for AES and QES as a separate step within a Maestro workflow, allowing them to easily sign with an eIDAS-compliant digital signatures at the end of the workflow.
Best practices for signer experience
When implementing Advanced Electronic Signatures, maintain data integrity by ensuring all documents are encrypted and stored securely. Prevent unauthorised access by using strong authentication methods like Phone Authentication or government identity document validation.
Keep signing steps minimal while still meeting legal requirements for advanced electronic signatures. Consider your signers' technical abilities and provide clear instructions to guide them through the verification process without frustration.
FAQs about Advanced Electronic Signatures
Is Docusign an Advanced Electronic Signature?
Docusign can provide Advanced Electronic Signatures (AES) by adding identity verification features to the signing process. These signatures uniquely link to signers and include digital certificates that meet eIDAS requirements for legal validity and security.
How do I create an Advanced Electronic Signature?
Creating an AES involves identity verification processes where signers provide valid ID documents and receive unique access codes. Docusign's workflow includes document authentication and tamper-evident sealing that detects any subsequent modifications.
Visit our AES Support Page to learn more.
How is an Advanced Electronic Signature obtained?
An Advanced Electronic Signature is obtained through a verification process that confirms the signer's identity using government-issued documents. Additional biometric checks can also be added to the verification process for even greater security. The process creates a unique digital certificate linking the signature to the verified identity.
What are the new Advanced Electronic Signature requirements for tax advisers from 6 April 2025?
From 6 April 2025, tax advisers receiving income tax or PAYE repayments on behalf of clients must use Advanced Electronic Signatures for P87, R40, and Marriage Allowance forms. Handwritten signatures will only be accepted for digitally excluded clients.
When is an Advanced Electronic Signature required?
Advanced Electronic Signatures are required for high-value / sensitive transactions, secure documents, and when regulatory compliance demands stronger identity verification. They're commonly used for consumer credit agreements, legal contracts, and when identity confirmation is essential.

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