Information Theory Based Evaluation of the RC4 Stream Cipher Outputs |
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Authors: | Evaristo Jos Madarro-Cap
Carlos Miguel Legn-Prez
Omar Rojas Guillermo Sosa-Gmez |
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Institution: | 1.Facultad de Matemática y Computación, Instituto de Criptografía, Universidad de la Habana, Habana 10400, Cuba; (E.J.M.-C.); (C.M.L.-P.);2.Facultad de Ciencias Económicas y Empresariales, Universidad Panamericana, Álvaro del Portillo 49, Zapopan 45010, Jalisco, Mexico; |
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Abstract: | This paper presents a criterion, based on information theory, to measure the amount of average information provided by the sequences of outputs of the RC4 on the internal state. The test statistic used is the sum of the maximum plausible estimates of the entropies , corresponding to the probability distributions of the sequences of random variables and , independent, but not identically distributed, where are the known values of the outputs, while is one of the unknown elements of the internal state of the RC4. It is experimentally demonstrated that the test statistic allows for determining the most vulnerable RC4 outputs, and it is proposed to be used as a vulnerability metric for each RC4 output sequence concerning the iterative probabilistic attack. |
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Keywords: | RC4 iterative probabilistic attacks entropy randomness |
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