关键词: 属性加密；函数加密；内积加密；分层访问结构；动态访问控制

Abstract: Against the backdrop of growing widespread adoption of data sharing and cloud computing technologies, the simultaneous realization of data privacy protection, flexible access control, and controlled computation over ciphertext has emerged as a key research area in the field of information security. Attribute-Based Inner Product Functional Encryption (ABIPFE) integrates the respective strengths of attribute-based encryption and functional encryption. Nevertheless, the majority of existing ABIPFE schemes are constructed based on static access structures, and cannot support the reuse of original ciphertexts when access policies evolve. This deficiency results in progressively increasing computational and communication overhead when such schemes are deployed in dynamic environments. To resolve this problem, this paper proposes an attribute-based inner product functional encryption scheme that supports dynamic expansion of access structures. This scheme incorporates two categories of extended encryption mechanisms. Instead of re-encrypting the original ciphertexts, the proposed scheme only generates additional ciphertext components for the newly added access structure parts, which effectively reduces the overall system overhead. Experimental implementation and performance evaluation demonstrate that across different attribute scales, message dimensions, and expansion depths, the proposed scheme outperforms the comparison schemes in the key generation, encryption, and decryption phases, while maintaining stable overall operation.

Key words: attribute-based encryption; functional encryption; inner-product encryption; hierarchical access structure; dynamic access control