An Information-theoretic Security Analysis of Honeyword

Fuente: arXiv
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Auteurs principaux: Su, Pengcheng, Cheng, Haibo, Li, Wenting, Wang, Ping
Format: Preprint
Publié: 2023
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author Su, Pengcheng
Cheng, Haibo
Li, Wenting
Wang, Ping
author_facet Su, Pengcheng
Cheng, Haibo
Li, Wenting
Wang, Ping
contents Honeyword is a representative "honey" technique that employs decoy objects to mislead adversaries and protect the real ones. To assess the security of a Honeyword system, two metrics--flatness and success-number--have been proposed and evaluated using various simulated attackers. Existing evaluations typically apply statistical learning methods to distinguish real passwords from decoys on real-world datasets. However, such evaluations may overestimate the system's security, as more effective distinguishing attacks could potentially exist. In this paper, we aim to analyze the security of Honeyword systems under the strongest theoretical attack, rather than relying on specific, expert-crafted attacks evaluated in prior experimental studies. We first derive mathematical expressions for the flatness and success-number under the strongest attack. We conduct analyses and computations for several typical scenarios, and determine the security of honeyword generation methods using a uniform distribution and the List model as examples. We further evaluate the security of existing honeyword generation methods based on password probability models (PPMs), which depends on the sample size used for training. We investigate, for the first time, the sample complexity of several representative PPMs, introducing two novel polynomial-time approximation schemes for computing the total variation between PCFG models and between higher-order Markov models. Our experimental results show that for small-scale password distributions, sample sizes on the order of millions--often tens of millions--are required to reduce the total variation below 0.1. A surprising result is that we establish an equivalence between flatness and total variation, thus bridging the theoretical study of Honeyword systems with classical information theory. Finally, we discuss the practical implications of our findings.
format Preprint
id arxiv_https___arxiv_org_abs_2311_10960
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle An Information-theoretic Security Analysis of Honeyword
Su, Pengcheng
Cheng, Haibo
Li, Wenting
Wang, Ping
Cryptography and Security
Honeyword is a representative "honey" technique that employs decoy objects to mislead adversaries and protect the real ones. To assess the security of a Honeyword system, two metrics--flatness and success-number--have been proposed and evaluated using various simulated attackers. Existing evaluations typically apply statistical learning methods to distinguish real passwords from decoys on real-world datasets. However, such evaluations may overestimate the system's security, as more effective distinguishing attacks could potentially exist. In this paper, we aim to analyze the security of Honeyword systems under the strongest theoretical attack, rather than relying on specific, expert-crafted attacks evaluated in prior experimental studies. We first derive mathematical expressions for the flatness and success-number under the strongest attack. We conduct analyses and computations for several typical scenarios, and determine the security of honeyword generation methods using a uniform distribution and the List model as examples. We further evaluate the security of existing honeyword generation methods based on password probability models (PPMs), which depends on the sample size used for training. We investigate, for the first time, the sample complexity of several representative PPMs, introducing two novel polynomial-time approximation schemes for computing the total variation between PCFG models and between higher-order Markov models. Our experimental results show that for small-scale password distributions, sample sizes on the order of millions--often tens of millions--are required to reduce the total variation below 0.1. A surprising result is that we establish an equivalence between flatness and total variation, thus bridging the theoretical study of Honeyword systems with classical information theory. Finally, we discuss the practical implications of our findings.
title An Information-theoretic Security Analysis of Honeyword
topic Cryptography and Security
url https://arxiv.org/abs/2311.10960