AI 中文总结
本研究针对图加密方案（GES）的结构泄露问题，分析现有方案PathGES的安全缺陷，提出Fragment Tree攻击，设计BlindGES防御方案并通过实验验证其性能提升。
AI 中文摘要
图加密方案（GES）支持在保障图数据安全外包的同时实现高效查询。本报告针对用于单对最短路径（SPSP）查询的GES中的结构泄露展开全面分析，整合了两项近期研究成果。首先，我们分析了PathGES方案，该方案通过轻重分解（HLD）和规范片段编码设计以抵御查询恢复攻击，分析发现PathGES的HLD分解存在显著失衡：在真实世界数据集上，超过99%的令牌-路径映射为一对一关系，这使得Falzon-Paterson攻击和路径长度的侧信道推理成为可能。其次，我们提出了Fragment Tree攻击，该攻击利用这些结构弱点恢复查询内容，在稀疏图上实现了高达10.24%的精确恢复率。第三，我们引入了增强方案BlindGES，其结合了分合机制和两级多映射索引，将一对一映射占比降至20%以下，将设置时间缩短50%，存储开销降低32%，并将路径长度泄露限制在1%以下。本报告在七个真实世界数据集上系统呈现了攻击方法、防御机制、安全证明及实验评估。
英文摘要
Graph encryption schemes (GES) enable secure outsourcing of graph data while supporting efficient queries. This report provides a comprehensive analysis of structural leakage in GES for single-pair shortest path (SPSP) queries, integrating findings from two recent works. First, we analyze PathGES, a scheme designed to resist query recovery attacks through heavy-light decomposition (HLD) and canonical fragment encoding. Our analysis reveals that PathGES suffers from significant imbalances in HLD decomposition, with over 99% of token-path mappings being one-to-one on real-world datasets, enabling both the Falzon-Paterson attack and side-channel inference of path lengths. Second, we present Fragment Tree attack that exploits these structural weaknesses to recover query contents, achieving up to 10.24% exact recovery on sparse graphs. Third, we introduce BlindGES, an enhanced scheme incorporating a Merge-and-Divide mechanism and two-level multimap index that reduces one-to-one mappings to below 20%, cuts setup time by 50%, reduces storage overhead by 32%, and limits path length leakage to under 1%. This report systematically presents attack methodologies, defense mechanisms, security proofs, and experimental evaluations on seven real-world datasets.
