面向隐私保护的相似PDF文件外包自动合并方法

传统的相似PDF文件合并往往需要用户先打开相关文件，并通过人工方式判断PDF文件间的相似性，最后借助在线工具完成相似文件合并动作。传统相似PDF合并方法不仅费时、费力，而且准确性易受限于主观判断。另一方面，在线合并方式存在用户PDF文件明文内容泄露风险，易导致数据安全和用户个人隐私问题。为了解决以上问题，本文提出了一种面向隐私保护的相似PDF文件外包自动合并方法。该方法根据PDF文件的结构特点并利用相似哈希函数提取文件特征信息，然后通过计算汉明距离来快速判断PDF文件间的相似度。此外，引入秘密分享技术实现相似PDF文件的安全外包自动合并。实验结果表明，本文所提出的方法能够实现相似PDF文件合并，并确保外包待合并数据的安全性。

A privacy-preserving automatic merging method for outsourcing similar PDF files

The traditional similar PDF file merging usually requires users to first open relevant files, then calculate the similarity between PDF files by manual means, and finally complete the similar file merging by using some online tools. This merging method is time-consuming and laborious, and the accuracy is limited by the subjective judgment. On the other hand, there is a risk that the plaintext content of users'' PDF files may be leaked in the outsourcing environment. It can cause data security and user privacy issues. To solve the above problems, this paper proposes a privacy-preserving automatic merging method for outsourcing similar PDF files. According to the structure characteristic of PDF file, it uses the similar hash function to extract the file feature information, and then quickly calculates the similarity between PDF files based on the hamming distance. Besides, we introduce the secret sharing technology to realize the secure automatic merging of similar PDF files. Experimental results show that the proposed method achieves the goal of merging similar PDF files, while ensuring the security of outsourced data to be merged.