Any-hop (k-hop) reachability query is one fundamental operation in graph data analysis and its performance affects the efficiency of various tasks in social Internet of Things. As graph data scale increases, data is often outsourced to cloud servers. To protect the privacy of graph data, it is necessary to encrypt the data before outsourcing. Existing schemes can only support privacy-preserving 2-hop reachability queries. Only one scheme can support privacy-preserving k-hop reachability queries, but it discloses topological information and the query results is not verifiable. Most serious deficiency is that its efficiency is not practical. To address these issues, we propose a verifiable strong privacy-preserving k-hop reachability query on encrypted data. This scheme not only supports efficient privacy-preserving k-hop reachability queries without leaking any network topological information but also uses blockchain to achieve verifiability of query results. The security analysis shows that our scheme is secure. Compared to existing k-hop reachability query scheme, our scheme greatly improves query efficiency (at least 6.4_105× faster when the number of nodes n≥100).

中文翻译：

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区块链辅助云上可验证的强隐私保护任意跳可达性查询


任意跳（k-hop）可达性查询是图数据分析中的一项基本操作，其性能影响着社交物联网中各种任务的效率。随着图数据规模的增加，数据通常外包到云服务器。为了保护图数据的隐私，在外包之前需要对数据进行加密。现有方案只能支持隐私保护的两跳可达性查询。只有一种方案可以支持隐私保护的k-hop可达性查询，但它公开了拓扑信息并且查询结果不可验证。最严重的缺陷是其效率不实用。为了解决这些问题，我们提出了一种针对加密数据的可验证的、强隐私保护的 k-hop 可达性查询。该方案不仅支持高效的隐私保护k-hop可达性查询而不泄露任何网络拓扑信息，而且利用区块链实现查询结果的可验证性。安全性分析表明我们的方案是安全的。与现有的k跳可达性查询方案相比，我们的方案极大地提高了查询效率（当节点数n≥100时至少快6.4_105倍）。