## 5 The Proposed Scheme
### The Designed Fast Searchable Decryption Algorithm
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Schemes** & **Setup** & **Keygen** & **Enc** & **ReEnc** & **Search** & **Dec** \\ \hline Deng [30] & \(\mathcal{V}_{A}t_{G}+t_{P}\) & \((\mathcal{V}_{M}\cdot log_{\mathcal{V}_{M}})t_{G}\) & \((\mathcal{V}_{M}+log_{\mathcal{V}_{L}})t_{G}\) & \(\mathcal{V}_{M}t_{G}\) & – & \(\mathcal{V}_{D}t_{G}+\mathcal{V}_{D}t_{P}\) \\ [PERSON] [26] & \((\mathcal{V}_{A}+t+6)t_{G}\) & \((\mathcal{V



Figure 6 shows the computation time of attribute-group-based user revocation for different numbers of attributes. We set the number of system users to \(\mathcal{V}_{\mathcal{U}}=512\) (with a tree depth of 10) and measured the revocation time when the user subset covered by the revoked attribute group contained 2 users. [PERSON] et al. [30] pointed out in their experiments that, in certain scenarios, user-level revocation is more efficient than attribute-level revocation. In particular, when the number of users is fixed, revoking a single user is significantly faster than revoking all the attributes associated with that user. In our scheme, revoking the user subset covered by an attribute group achieves millisecond-level efficiency. Specifically, with 512 users and 50 attributes in the framework, revoking a single attribute group covering 2 users takes only 629 ms. Although the time required for a single ciphertext update and user revocation in our scheme is slightly higher than that in [PERSON]'s scheme [30], our approach simultaneously revokes multiple users based on the attribute group coverage. Moreover, our scheme supports searchability and enables decryption after efficient keyword-group-based user revocation, resulting in improved overall revocation performance for the methodology. Figure 7 shows the computation time of user revocation based on keyword groups under different numbers of keywords. We set the number of attributes in the framework to 10 and measured the revocation time when the user subset covered by the revoked keyword group contained two users. The results are compared with the two methods proposed by [PERSON] [31]. For keyword-based user revocation, [PERSON]'s RKS [31] method exhibits a relatively long running time, exceeding 10 s. In contrast, our method incurs lower computational overhead and performs comparably to [PERSON]'s improved RKS+ method. Notably, when handling large-scale revocations, our scheme demonstrates better scalability and performance, achieving millisecond-level efficiency. Specifically, when the framework has 512 users and 1000 keywords, revoking a single keyword group covering 2 users takes approximately 1 s.

Figure 5: Latency of encryption, search, and decryption vs. attribute/keyword counts. Figure 6: Revocation performance of users covered by attribute groups. Through comparative analysis with the experiments of [PERSON] [30] and [PERSON] [31], it can be observed that our proposed scheme demonstrates superiority in user revocation based on both attribute and keyword group coverage. When dealing with different scenarios such as ciphertext (corresponding to user-level attribute revocation) and index updates (corresponding to keyword revocation), our scheme consistently maintains low computational overhead and exhibits strong scalability, making it well-suited for large-scale systems. ## 8 Conclusions

This paper proposes ABE-RS, a searchable and revocable attribute-based encryption scheme designed for dynamic video anomaly detection. By combining a user management tree with attribute and keyword revocation and incorporating an inverted index structure, ABE-RS enables fine-grained, flexible access control and an efficient encrypted search. The scheme is particularly effective in scenarios requiring frequent ciphertext and index updates, maintaining low computational overhead and strong scalability.