<p>Integrating blockchain technology into Cloud-based Internet of Things (CIoT) environments is essential for ensuring secure, anonymous, and accountable data sharing. This paper presents the Blockchain-Enabled Secure and Anonymous Data Sharing (BS-ADS) system, which addresses critical challenges related to confidentiality, integrity, anonymity, and revocation in CIoT ecosystems. Our solution combines Aggregate Key Searchable Encryption (AKSE) with blockchain to enable secure, efficient data exchange among CIoT devices, cloud servers, and data users. The decentralized, immutable nature of blockchain ensures transparency and accountability while preserving user anonymity. The system also incorporates efficient revocation mechanisms to prevent compromised devices from accessing sensitive data. Through both theoretical and experimental evaluations, we demonstrate that BS-ADS achieves low computational and communication overhead, efficient blockchain consumption, and robust security guarantees. Our framework provides a scalable, effective solution for secure data sharing in CIoT environments, ensuring data confidentiality, integrity, privacy, and transparency. This system is a promising foundation for applications in smart cities, healthcare, and industrial IoT systems.</p>