ISO 14533-2:2021

Overview

ISO 14533-2:2021 - "Processes, data elements and documents in commerce, industry and administration - Long term signature - Part 2: Profiles for XML Advanced Electronic Signatures (XAdES)" - defines how to make XAdES digital signatures verifiable over long periods. The standard does not change core digital-signature algorithms; instead it profiles XAdES (the extended XML signature model defined by ETSI EN 319 132) to ensure long-term validation and interoperability.

Key topics and technical requirements

• Long-term signature profiles: Defines three profile levels to support longevity and validation:
  • XAdES‑T (signature with timestamp) - intermediate form that records signing time.
  • XAdES‑X‑Long - adds validation data necessary for later verification.
  • XAdES‑A (archival XAdES) - adds archival timestamps or protections for long-term availability.
• Verification goals: Ensure signing time is identifiable, enable detection of illegal alterations, and preserve validation data and signer identity for the long term.
• Element-level profiling: Specifies required-level categories for XAdES elements:
  • Mandatory (M), Optional (O), Conditional (C) - and rules for selecting or declaring conditional elements.
• Interoperability & conformance: Implements supplier’s declaration of conformance (Annex A) for first-party declarations and describes expected XML namespaces and prefixes (including XAdES 1.4.1 support).
• Normative references: Profiles ETSI EN 319 132-2 and relies on XML Signature Syntax and Processing (W3C). Annexes cover supplier declarations, timestamp token structure (Annex B) and differences with European EN profiles (Annex C).
• Operational guidance: Includes procedures and timing diagrams for long-term signature operations and handling of unimplemented elements during validation.

Practical applications and who uses it

• Software developers and vendors building XML signature libraries and document management systems that require long-term digital signature validation.
• Trust service providers (certificate authorities, timestamping authorities) implementing interoperable timestamping and validation data delivery.
• Government, legal, financial and archival institutions that must preserve signed electronic records for regulatory or evidentiary purposes.
• Integrators and auditors who need to verify conformance and declare supplier compliance for long-term signature profiles.

Related standards

• ISO 14533-1 - Long term signature profiles for CAdES
• ETSI EN 319 132-2 - XAdES digital signatures (extended signatures)
• W3C XML Signature Syntax and Processing
• ISO/IEC 18014 (referenced for archiving-type timestamps)

ISO 14533-2:2021 is essential when implementing reliable, interoperable XAdES-based solutions for long-term validation of XML digital signatures.