Resumen: The rise of distributed architectures in Internet of Things (IoT) environments has significantly advanced both data processing and artificial intelligence. Notably, Multi-access Edge Computing (MEC) represents a distributed form of the Edge Computing paradigm, focussing on heterogeneous protocol management. In contrast, Federated Learning (FL) is an application-level framework designed to enable decentralised Machine Learning (ML) across devices without centralising data. Nevertheless, the combination of both technologies enables the creation of more efficient, scalable, and responsive systems. However, their integration into IoT brings substantial security challenges, including data poisoning, model manipulation, and the insertion of false nodes, all of which threaten the reliability of FL systems. Blockchain technology emerges as a promising solution to these challenges. It offers a decentralised, transparent, and immutable framework that ensures the authenticity and verification of data across the network. Through blockchain, node interactions are automated and secured, enhancing the integrity and trust in the learning process. This article proposes a blockchain-based architecture for FL within MEC-IoT systems, designed to mitigate security threats. The architecture emphasises data integrity, secure node interactions, and transparent audit trails while maintaining optimal model performance and accuracy, even under attack. It highlights the low resource consumption and minimal time overhead of blockchain integration, ensuring efficiency is not compromised. This integrated approach improves data security, supports secure collaborative learning, and fosters a more resilient and trustworthy IoT ecosystem. Idioma: Inglés DOI: 10.1145/3767740 Año: 2026 Publicado en: ACM Transactions on Internet Technology 26, 1 (2026), 9 [30 pp.] ISSN: 1533-5399 Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2024-158682OB-C32 Financiación: info:eu-repo/grantAgreement/ES/DGA/T21-23R Financiación: info:eu-repo/grantAgreement/ES/MCIU/PID2023-151467OA-I00 Financiación: info:eu-repo/grantAgreement/EUR/MICINN/TED2021-131115A-I00 Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2022-142332OA-I00 Tipo y forma: Article (Published version) Área (Departamento): Área Lenguajes y Sistemas Inf. (Dpto. Informát.Ingenie.Sistms.)