A Blockchain Integrated Attribute Based Searchable Encryption Framework for Secure Privacy Preserving and Auditable Cloud Data Access

The rapid growth of cloud computing and decentralized applications has intensified the demand for secure fine grained and auditable data access control mechanisms. Although Ciphertext Policy Attribute Based Encryption (CP-ABE) provides flexible authorization existing solutions often suffer from high computational overhead limited scalability and weak trust assumptions caused by centralized authorities. Moreover traditional CP-ABE schemes offer limited support for secure data retrieval and transparent auditing in large scale cloud environments. This paper proposes a blockchain integrated attribute based searchable encryption framework that enables secure privacy preserving and verifiable access to encrypted cloud data. The proposed architecture combines CP-ABE with proxy re encryption and delegated decryption to significantly reduce computational costs for data owners and users. Encrypted data are stored in the Inter Planetary File System (IPFS) while access policies metadata and audit records are immutably recorded on the blockchain to ensure integrity and accountability. In addition the framework supports hidden access policies efficient attribute revocation and secure keyword search over encrypted data without revealing sensitive information. A comprehensive security analysis demonstrates resistance to chosen plaintext attacks keyword guessing attacks and unauthorized access while preserving user privacy. Furthermore a comparative performance analysis shows that the proposed framework achieves improved efficiency and scalability compared to existing blockchain based ABE schemes. These features make the proposed solution suitable for secure data sharing in cloud computing, smart cities, and decentralized information systems. Keywords: ABE, Attribute Based Encryption, CP-ABE, Blockchain , IPFS , Access Control , Decentralized Storage .