Recently, Wu et al. [Int. J. Theor. Phys. 58, 1854, (2019)] found a serious information leakage problem in Ye and Ji's quantum private comparison protocol [Int. J. Theor. Phys. 56, 1517, (2017)], that is, a malicious participant can steal another's secret data without being detected through an active attack means. In this paper, we show that Wu et al.'s attack means is also effective for several other existing protocols, including the ones proposed by Ji et al. and Zha et al. [Commun. Theor. Phys. 65, 711, (2016) and Int. J. Theor. Phys. 57, 3874, (2018)]. In addition, we propose a passive attack means, which is different from Wu et al.'s active attack in that the malicious participant can easily steal another's secret data only by using his own secret data after finishing the protocol. Furthermore, we find that several other existing quantum private comparison protocols also have such an information leakage problem. In response to the problem, we propose a simple solution, which is more efficient than the ones proposed by Wu et al., because it does not consume additional classical and quantum resources. We also make some comments on this problem.

中文翻译：

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几种量子私有比较协议的密码分析与改进

最近，吴等人。[国际。J. 理论。物理。58, 1854, (2019)] 在叶和季的量子私有比较协议中发现了严重的信息泄漏问题 [Int. J. 理论。物理。56, 1517, (2017)]，即恶意参与者可以通过主动攻击手段在不被发现的情况下窃取他人的秘密数据。在本文中，我们表明 Wu 等人的攻击手段对其他几种现有协议也有效，包括 Ji 等人提出的协议。和 Zha 等人。[社区。理论。物理。65, 711, (2016) 和 Int. J. 理论。物理。57, 3874, (2018)]。此外，我们提出了一种被动攻击手段，与Wu等人的主动攻击不同，恶意参与者在完成协议后仅使用自己的秘密数据就可以轻松窃取他人的秘密数据。此外，我们发现其他几个现有的量子私有比较协议也存在这样的信息泄漏问题。针对这个问题，我们提出了一个简单的解决方案，它比 Wu 等人提出的方案更有效，因为它不消耗额外的经典和量子资源。我们也对这个问题发表一些意见。