IMPROVING SECURITY IN CLOUD STORAGE: AUDITING BY IDENTITY, HIDDEN DATA, AND SECURE SHARING

Abstract

Cloud storage services enable users to outsource data and share it remotely, but ensuring both integrity and privacy of sensitive information remains a critical challenge. Traditional remote data integrity auditing verifies correctness of stored files; however, in applications such as Electronic Health Records (EHRs), directly sharing files risks exposing confidential data, while encrypting entire files hides sensitive content but limits usability. To overcome this, we propose an identity-based remote data integrity auditing scheme that integrates sensitive information hiding with secure data sharing. The approach employs a sanitizer to replace sensitive data blocks with sanitized versions and transform their signatures into valid ones, enabling integrity verification without revealing hidden content. Additionally, proxy re-signatures facilitate efficient and secure user revocation, while a blockchain-based decentralized auditing process eliminates reliance on a trusted third party, thereby enhancing transparency and reliability. Security and performance evaluations demonstrate that the proposed scheme achieves strong privacy preservation, reduced computational overhead, and practical efficiency for realworld cloud storage applications.