Finding the original point set hidden among chaff
Finding the original point set hidden among chaff
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DOI：
10.1145/1128817.1128845
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发表时间：
2006-03
期刊：
影响因子：
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通讯作者：
E. Chang;Ren Shen;Francis Weijian Teo
中科院分区：
文献类型：
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作者：
E. Chang;Ren Shen;Francis Weijian Teo
在生物特征识别中，指纹通常被表示为一组细节点，这些细节点是2D点。一种保护指纹模板的方法[4]通过将随机点(称为箔条)添加到原始点集来隐藏细节节点。在不可能添加更多点或添加了足够数量的点之前，受两个点不能彼此靠近的要求的约束，箔条点被逐个添加。因此，如果原始模板由S点数组成，且箔条点数和原始点数之和为m，则暴力攻击者有望检查m的一半选择S寻找原始点数的可能性。产生的谷壳似乎是“随机的”，特别是如果细节点也是以同样的方式随机产生的。事实上，暴力攻击者所需的搜索次数已经被用来衡量该方法的安全性。在这篇文章中，我们给出了一个观察，它导致了一种区分细节点和谷壳的方法。大量的模拟表明，我们的攻击者可以找到比蛮力搜索更好的原始文件。例如，当S=1并且预计箔条点数约为313时，我们的攻击者平均进行约100次搜索。我们的结果强调了需要采用更严格的安全概念来进行模板保护。我们还给出了由该示意图引起的熵损失的经验下限。
In biometric identification, a fingerprint is typically represented as a set of minutiae which are 2D points. A method [4] to protect the fingerprint template hides the minutiae by adding random points (known as chaff) into the original point set. The chaff points are added one-by-one, constrained by the requirement that no two points are close to each other, until it is impossible to add more points or sufficient number of points have been added. Therefore, if the original template consists of s points, and the total number of chaff points and the original points is m, then a brute-force attacker is expected to examine half of m chooses s possibilities to find the original. The chaff generated seem to be "random", especially if the minutiae are also randomly generated in the same manner. Indeed, the number of searches required by the brute-force attacker has been used to measure the security of the method. In this paper, we give an observation which leads to a way to distinguish the minutiae from the chaff. Extensive simulations show that our attacker can find the original better than brute-force search. For e.g. when s = 1 and the number of chaff points is expected to be about 313, our attacker on average takes about 100 searches. Our results highlight the need to adopt a more rigorous notion of security for template protection. We also give an empirical lower bound of the entropy loss due to the sketch.