XAdES

XAdES (ETSI EN 319 132) is the standard for embedding electronic signatures and seals in XML data, used for e-invoicing and long-term validation.

XAdES (XML Advanced Electronic Signatures) is the ETSI standard (EN 319 132) that defines how an electronic signature or electronic seal is embedded in or associated with XML data. It builds on the W3C XML Signature (XMLDSig) specification, adding the extra elements - signing time, signer certificate, policy references, and later validation data - that AdES signature formats require for long-term legal evidence.

A signature can be enveloped (placed inside the signed XML document), enveloping (wrapping the signed data), or detached (a separate file referencing the signed data). Like the other AdES formats, XAdES defines incremental forms - from a baseline signature (B-B) through a timestamped form (B-T) to long-term forms (B-LT, B-LTA) that add certificate and revocation data over time to support Long-Term Validation. Older deployments often still use the forms from the predecessor specification, ETSI TS 101 903 - XAdES-BES, -T, -XL and -A - so a system that has to accept incoming signatures usually has to handle both those and the baseline forms.

It suits structured XML data such as e-invoices or government message exchanges, and, combined with a qualified certificate and a QSCD, can produce a qualified electronic signature. Which XML format a public sector body has to recognise is set by implementing act: Commission Implementing Regulation (EU) 2026/248 now lays that down and repeals Implementing Decision (EU) 2015/1506, which did so before. XAdES sits next to CAdES for binary data, PAdES for PDF and JAdES for JSON.