Securing Cloud Access with Enhanced Attribute-based Cryptography using Bilinear Group Noise-Based Authentication with Optimized Ciphertext Outsourcing

The growth of cloud computing has made ensuring fine-grained access to outsourced data increasingly essential. Attribute-Based Cryptography (ABC) provides flexible access control by using user attributes instead of identities. Existing methods fail to address user revocation effectively and lack complete encryption during policy updates. However, ABC schemes remain vulnerable to collusion and attribute inference attacks, where unauthorized users combine their attributes or keys to gain illicit access, posing significant security risks. To overcome these challenges, the Bilinear Group Noise-Based Authentication with Optimized Ciphertext Outsourcing (BGNBA-OCO) approach combines bilinear pairing and noise-based encryption to enhance security against collusion. The attribute-based secret key mechanism ensures that only authorized users can decrypt the data. The proposed BGNBA-OCO enables secure ciphertext outsourcing, thereby reducing local computation overhead. It also supports user revocation without requiring re-encryption of the entire dataset. The BGNBA-OCO approach achieves an encryption time of 6.21, decryption time of 4.32, and execution time of 9.46 for 100 key sizes.