China: TC260 adopted Guidelines on Identification Methods for AI-Generated Synthetic Text Content

On 28 August 2025, the National Technical Committee on Cybersecurity Standardisation (TC260) adopted the Cybersecurity Standard Practice Guide—Artificial Intelligence Generated Synthetic Content Identification Method: File Metadata Implicit Identification for Text Files (V1.0-202508), a technical guide aligned with the mandatory national standard GB 45438-2025 Cybersecurity Technology—Identification Methods for AI-Generated Synthetic Content. The Practice Guide specifies detailed implicit metadata identification methods for text files generated or synthesised by artificial intelligence technologies, including implementation schemes for multiple file formats such as Office Open XML (OOXML), Uniform Office Document Format (UOF), Portable Document Format (PDF), Open Fixed layout Document (OFD), Markdown, Xmind, and POSM/POSF. It sets out requirements for storage locations, metadata elements, encoding methods, and labelling structures, mandating fields such as Label, ContentProducer, ProduceID, ContentPropagator, and PropagateID. The Guide provides pseudocode for metadata reading and writing procedures, along with illustrative implementation examples for each supported format, thereby establishing a framework for artificial intelligence text content generation service providers and internet information text content propagation service providers to conduct implicit metadata identification in compliance with national standards and the Administrative Measures for Artificial Intelligence Generated Synthetic Content Labelling.