A Secure Distributed File Sharing System with Key Aggregate Cryptography for Cloud Storage

Cloud computing has been widely accepted as a technology that allows users to access applications and files from any location through the internet.In this work, a secure cloud storage model was developed using the Key Aggregate Cryptosystem (KAC), which provides compact and efficient key management.The method was designed so that a constant-size aggregate key could be generated, allowing multiple ciphertexts to be decrypted without the need for multiple keys.The proposed system was implemented with five phases: setup, key generation, encryption, extraction, and decryption.Files were encrypted before storage, and decryption rights were shared through a single aggregate key.This ensured confidentiality, reduced key management complexity, and enabled selective file sharing.The performance of the system was evaluated, and it was observed that encryption and decryption were efficient while the aggregate key size remained constant.The study concluded that KAC can provide secure and scalable file sharing in cloud storage systems.The system is suitable for both individual users and enterprises where controlled access and efficient data sharing are required.Future improvements can include testing with larger datasets, integration with hybrid encryption, and resilience against advanced security threats.