On information-theoretic metrics for symmetric-key encryption and privacy
On information-theoretic metrics for symmetric-key encryption and privacy
复制标题
关于对称密钥加密和隐私的信息论度量
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
M. Médard
中科院分区：
文献类型：
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作者：
F. Calmon;Mayank Varia;M. Médard
大多数实际的安全系统并没有达到完美的保密性，即计算无界的窃听者所观察到的信息并不是独立于明文消息的。尽管如此，仍可能存在窃听者无法可靠推断的明文属性。在本文中，我们以作者以前的工作为基础，引入了新的界限，用于量化攻击者在非完美保密制度下估计明文某些功能的程度。特别是，我们给出了估计明文目标函数的最小均方误差的下界，假设明文的某类函数是已知难以（或容易）推断的，无论是通过安全系统的设计还是通过对对手施加的限制。我们演示了如何应用这些边界来描述对称密钥加密方案的基本安全属性。我们的研究结果还揭示了隐私保护系统中存在的基本隐私-效用权衡。
Most practical security systems do not achieve perfect secrecy, i.e. the information observed by a computationally unbounded eavesdropper is not independent of the plaintext message. Nevertheless, there may still be properties of the plaintext that the eavesdropper cannot reliably infer. In this paper, we build on previous work by the authors and introduce new bounds that are used to quantify how well an adversary can estimate certain functions of the plaintext in the non-perfect secrecy regime. In particular, we present lower bounds for the minimum-mean-squared-error of estimating a target function of the plaintext given that a certain class of functions of the plaintext is known to be hard (or easy) to infer, either by design of the security system or by restrictions imposed on the adversary. We demonstrate how these bounds can be applied to characterize fundamental security properties of symmetric-key encryption schemes. Our results also shed light on the fundamental privacy-utility tradeoff that exists in privacy-preserving systems.