ISO 14533-3:2025

Overview

ISO 14533-3:2025 - "Processes, data elements and documents in commerce, industry and administration - Long-term signature - Part 3: Profiles for PDF Advanced Electronic Signatures (PAdES)" defines profiles and required elements that make PDF digital signatures verifiable over the long term. The standard focuses on PAdES-based mechanisms (as used with CAdES signatures in PDF defined by ISO 32000-2) to ensure signing time can be identified, illegal alterations are detectable, and interoperability is achieved. It does not change low‑level signature algorithms or add new signature technical specifications.

Key topics and requirements

• Profiles defined:
  • PAdES-T - profile for timestamping signatures (signature timestamp stored in a signature attribute or subsequent object such as a document timestamp).
  • PAdES-A - archival profile that protects long‑term availability and integrity of validation data and signature-related information.
• Element requirement levels: each profile element is classified as Mandatory (M), Optional (O), Conditional (C) or Prohibited (P); mandatory elements must be implemented; conditional elements require separate specifications.
• Conformity rules: Implementations must include all Mandatory elements and document handling of Conditional elements. First‑party conformity requires a supplier’s declaration of conformity (Annex A).
• Supporting structures and topics included in the document: document security store dictionary, Validation‑Related Information (VRI) dictionary, document timestamps, timestamp token structure (Annex C), profiles for timestamp‑only usage (PAdES‑DT/DTA - Annex B), and handling of multiple signatures.
• Normative reference: ISO 32000‑2 (PDF 2.0) for PDF and PAdES/CAdES usage.

Applications and practical value

• Ensures long‑term verifiability of electronically signed PDF documents for archiving, legal evidence, regulatory compliance, and enterprise document workflows.
• Enables software vendors to build interoperable PDF signing and validation tools that preserve signature validity over many years.
• Supports trust service providers, timestamp authorities, and certification authorities in delivering services that meet defined long‑term signature profiles.
• Assists auditors and records managers to assess and certify long‑term signature handling in document management systems.

Who should use this standard

• PDF signing and validation software developers (desktop, server, cloud)
• Trust service providers, time‑stamping authorities and certification authorities
• Records management and archiving professionals
• Legal, compliance and IT security teams implementing long‑term digital evidence procedures

Related standards

• ISO 32000‑2 (PDF 2.0) - referenced for PDF and PAdES/CAdES usage
• ISO 14533 series - related parts on long‑term signature concepts and processes

Keywords: ISO 14533-3:2025, PAdES, PAdES-T, PAdES-A, PDF Advanced Electronic Signatures, long-term signature, timestamp, digital signature verification, ISO 32000-2.