###### Abstract
However, the verification techniques in these schemes rely on specific indexing structures, lacking generality and impeding the expandability of the scheme's expressive capabilities. In addition, in cases where users are dishonest or maliciously repudiate, such methods still cannot guarantee a fair verification of search results. Blockchain is a distributed database with the property of immutability and decentralization. Compared to traditional networks, the information recorded on the blockchain is more reliable, addressing the issue of mutual distrust among different parties. Therefore, introducing blockchain as a trusted third party into searchable encryption schemes can effectively resolve the problem of fair verification between servers and users. [PERSON] et al. [30] proposed a fair verifiable DSSE scheme by utilizing smart contracts to replace the server. [PERSON] et al. [31] achieved ciphertext retrieval in distributed storage and utilized blockchain for verification. [PERSON] et al. [32] and [PERSON] et al. [33] both achieved static verification of search results on the blockchain by using message authentication codes. However, static verification cannot meet the requirements for frequent data updates in the 6G network. These schemes can be combined with blockchain technology to achieve the verification of search results and mitigate the potential for dishonest or malicious denial by users. However, there are still some challenges and issues that need to be addressed. The existing blockchain-based verifiable DSSE schemes either lack consideration for forward privacy and access control, or trade frequent transactions for ciphertext retrieval and result verification. The reason for frequent transactions is that both retrieval and verification operations are executed on the blockchain, which reduces the efficiency of the scheme. Hence, the challenge of devising an efficient and comprehensive DSSE scheme for 6G-based intelligent application systems remains an unresolved issue. In response to the requirements of low latency, high security, and high reliability in 6G-based intelligent application systems, we propose a novel blockchain-based DSSE scheme, referred to as VSSE. Firstly, VSSE possesses forward privacy to consist file-injection attacks, which greatly enhances the security of the scheme. We construct a state chain structure to achieve forward privacy. For each update, a new state is randomly generated for the keyword, and each state is linked by encrypted entries. The cloud server cannot deduce the most recent state of the keyword by relying on past search tokens. Building upon this foundation, to further enhance the efficiency of the scheme, our approach establishes the search operations on the server side, thereby reducing the frequency of interactions with the blockchain during the search and contributing to efficiency improvement. Next, in order to comprehensively meet the high reliability requirements of 6G systems, our scheme validates search results based on the tamper-resistant property of the blockchain. Once the search is completed, the results are sent from the server to the blockchain. After that, the blockchain performs verification based on verification information and returns the verification result and the search result to the data user. Meanwhile, we introduce a bitmap index structure to represent file identifiers and combine it with message authentication code (MAC) technology to attain dynamic verification of outcomes. Moreover, VSSE encompasses access control functionality, enabling users with distinct permissions to access relevant files. The aforementioned designs collectively fulfill the characteristics of 6G-based intelligent application systems. Ultimately, our scheme's security analysis and experimental outcomes affirm its robust security and operational efficiency.