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As part of the Department of Taxation’s plan to upgrade its electronic invoicing system, the XAdES digital signature standard is expected to be rolled out starting in November 2026. FPT.eSign, FPT’s digital signing service, has already been upgraded and is operating in accordance with the XAdES standard, ready to meet the updated technical requirements of Vietnam’s electronic invoicing system.
The Department of Taxation’s Roadmap for Implementing the XAdES Digital Signature Standard
On October 16, 2026, the Department of Taxation issued Official Dispatch No. 7714/CT-CĐS, outlining its plan to upgrade the information technology infrastructure supporting the implementation of electronic invoices and electronic documents in accordance with Decree No. 254/2026/NĐ-CP and Circular No. 91/2026/TT-BTC.
The upgrade plan comprises four phases, running from September through December 2026, and focuses on updating functions for registration, receipt, processing, lookup, and transmission of electronic invoice data. A key component of Phase 3 is the implementation of digital signatures based on the XAdES standard, scheduled for November 2026.
Regarding digital signature standards, Decision No. 1233/QĐ-CT, issued by Department of Taxation on August 27, 2026, establishes requirements for the components containing electronic invoice and document business data, as well as data transmission methods between organizations and tax authorities. The Decision also sets out a roadmap for upgrading digital signing systems, including a transition period during which both DSig and XAdES signatures will be accepted in parallel, with DSig acceptance continuing until April 9, 2027.
As digital signature technical standards continue to evolve, understanding the nature and scope of XAdES is becoming increasingly important for businesses using electronic invoicing systems. This article explains the XAdES standard, examines the role of digital signatures in electronic invoicing workflows, and introduces the XAdES capabilities of FPT’s digital signature solution. It aims to help businesses assess whether their existing systems meet the updated technical requirements and make informed decisions when selecting a suitable solution.
The XAdES Standard and the Role of Digital Signatures in Electronic Invoicing
XAdES (XML Advanced Electronic Signatures) is an advanced electronic signature standard for XML-based data, specified in the ETSI EN 319 132 series of standards developed by the European Telecommunications Standards Institute (ETSI). Built on XML Digital Signature (XMLDSig), XAdES extends the signature structure by incorporating additional qualifying properties to support signature validation and long-term verification. Depending on the implementation level, XAdES can also incorporate information about signing time, digital certificates, and evidence required for long-term signature validation.
From a technical perspective, XMLDSig provides mechanisms for creating and verifying XML-based digital signatures, enabling systems to verify the integrity of signed content and authenticate the signatory. The fundamental difference lies in the signature structure and the additional information associated with it, rather than in replacing the underlying signing algorithms or digital certificates. Therefore, upgrading a system to support XAdES does not necessarily require businesses to replace their existing digital certificates.
Put simply, XMLDSig can be compared to an electronic seal placed on a document, allowing recipients to verify that the document has been signed and determine whether its contents have been altered after signing. XAdES extends this concept by supplementing the electronic seal with a standardized set of validation-related information.
For example, when an electronic invoice is signed using XMLDSig, the system can verify the signature and the integrity of the signed data. With XAdES, the signature can additionally incorporate signing-time information, digital certificate details, or other validation evidence, depending on the implementation level. This additional information enables more comprehensive signature validation, particularly when verification is required long after the original signing event. In other words, XAdES does not replace the core functionality of XMLDSig. Instead, it extends the ability to provide and retain information needed for signature validation.
In electronic invoicing, digital signatures play an important role in authenticating the signatory and ensuring data integrity where required by law. When electronic invoices are generated, digitally signed, and transmitted in XML format, digital signatures enable the relevant parties to validate the signatures and detect modifications to the signed data.
This is particularly relevant for businesses processing large volumes of invoices or integrating electronic invoicing systems with enterprise resource planning (ERP), point-of-sale (POS), and accounting software. In such environments, digital signing workflows often involve multiple interconnected software components. Consequently, support for the appropriate digital signature format must be assessed across the entire data processing and transmission workflow, rather than solely at the digital certificate level.
From an implementation perspective, XAdES compatibility involves more than the ability to generate signatures that conform to the standard. It also depends on how digital signing software, electronic invoicing platforms, and integrated system components work together to process data.
For businesses with existing systems, assessing XAdES compatibility helps determine whether software modifications, configuration changes, or adjustments to integration workflows are necessary to meet the applicable technical requirements. XAdES support is also an important consideration when selecting a digital signature provider, particularly as the technical standards governing electronic invoicing systems continue to evolve.
FPT.eSign Already Supports the XAdES Digital Signature Standard
As the Department of Taxation prepares to implement the XAdES digital signature standard, FPT.eSign had already been upgraded to support XAdES and was operating in accordance with the standard before the new implementation roadmap was announced. The service is therefore well-positioned to meet the evolving technical requirements of Vietnam’s electronic invoicing system. FPT.eSign’s technological capabilities have also been recognized through its distinction as the only remote digital signature solution to receive a five-star rating at the 2022 Sao Khue Awards, as well as a QTSP-related certification issued by Tayllorcox, reflecting alignment with relevant European trust-service standards.
Within FPT’s electronic invoicing ecosystem, FPT.eSign is directly integrated with FPT.eInvoice, enabling businesses to digitally sign invoices as part of the invoice creation and issuance process without requiring a USB token. This integration embeds digital signing into the electronic invoicing workflow, reducing manual operations and facilitating more efficient electronic document management.
For existing customers using FPT.eInvoice and FPT.eSign, FPT.eSign’s existing XAdES support provides reassurance amid evolving technical requirements. For businesses exploring digital signature solutions or considering switching providers, FPT.eSign is an option worth considering, with XAdES support already implemented and operational, alongside direct integration with FPT’s electronic invoicing ecosystem.
