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arXiv · 2404.16853

Expectation Entropy as a Password Strength Metric

Khan Reaz·Gerhard Wunder
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Abstract

The classical combinatorics-based password strength formula provides a result in tens of bits, whereas the NIST Entropy Estimation Suite give a result between 0 and 1 for Min-entropy. In this work, we present a newly developed metric -- Expectation entropy that can be applied to estimate the strength of any random or random-like password. Expectation entropy provides the strength of a password on the same scale as an entropy estimation tool. Having an 'Expectation entropy' of a certain value, for example, 0.4 means that an attacker has to exhaustively search at least 40\% of the total number of guesses to find the password.

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Khan Reaz, Gerhard Wunder. 2024-03-18. Expectation Entropy as a Password Strength Metric. https://doi.org/10.1109/cns56114.2022.9947259

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