VOHSABE‐SC: A Verifiable Outsourced Hierarchical Searchable Attribute‐Based Encryption Scheme Supported by Smart Contracts

ABSTRACT

Cloud data sharing often depends on trusted third parties, involves redundant access policies, and places substantial computational burdens on clients. To address these challenges, we propose VOHSABE‐SC, a verifiable outsourced hierarchical searchable attribute‐based encryption scheme supported by smart contracts. VOHSABE‐SC follows an on‐chain/off‐chain architecture: ciphertext payloads are stored in the InterPlanetary File System, while encrypted indexes and trapdoors are recorded on the blockchain, which effectively balances data reliability and storage overhead. To reduce redundant computation and ciphertext size, we design a redundancy‐pruned hierarchical access structure that allows node reuse across related policies. Moreover, VOHSABE‐SC outsources part of the encryption workload to edge nodes and offloads pairing‐intensive pre‐decryption to InterPlanetary File System, thereby significantly lowering the online cost for data users. Finally, smart contracts perform multi‐keyword matching and key‐hash verification to provide verifiable search and integrity checking. Experimental results show that VOHSABE‐SC delivers better overall performance than representative baselines while preserving security.