{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,11]],"date-time":"2025-11-11T15:51:48Z","timestamp":1762876308271,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,7,14]],"date-time":"2021-07-14T00:00:00Z","timestamp":1626220800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>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 H(jt|zt), corresponding to the probability distributions P(jt|zt) of the sequences of random variables (jt)t\u2208T and (zt)t\u2208T, independent, but not identically distributed, where zt are the known values of the outputs, while jt 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.<\/jats:p>","DOI":"10.3390\/e23070896","type":"journal-article","created":{"date-parts":[[2021,7,14]],"date-time":"2021-07-14T10:13:42Z","timestamp":1626257622000},"page":"896","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Information Theory Based Evaluation of the RC4 Stream Cipher Outputs"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5004-2960","authenticated-orcid":false,"given":"Evaristo Jos\u00e9","family":"Madarro-Cap\u00f3\u00a0","sequence":"first","affiliation":[{"name":"Facultad de Matem\u00e1tica y Computaci\u00f3n, Instituto de Criptograf\u00eda, Universidad de la Habana, Habana 10400, Cuba"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6104-9671","authenticated-orcid":false,"given":"Carlos Miguel","family":"Leg\u00f3n-P\u00e9rez\u00a0","sequence":"additional","affiliation":[{"name":"Facultad de Matem\u00e1tica y Computaci\u00f3n, Instituto de Criptograf\u00eda, Universidad de la Habana, Habana 10400, Cuba"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0681-3833","authenticated-orcid":false,"given":"Omar","family":"Rojas","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias Econ\u00f3micas y Empresariales, Universidad Panamericana, \u00c1lvaro del Portillo 49, Zapopan 45010, Jalisco, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7793-896X","authenticated-orcid":false,"given":"Guillermo","family":"Sosa-G\u00f3mez","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias Econ\u00f3micas y Empresariales, Universidad Panamericana, \u00c1lvaro del Portillo 49, Zapopan 45010, Jalisco, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1007\/3-540-49649-1_26","article-title":"Analysis methods for (Alleged) RC4","volume":"Volume 1514","author":"Knudsen","year":"1998","journal-title":"Lecture Notes in Computer Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1007\/10718964_18","article-title":"Iterative probabilistic cryptanalysis of RC4 keystream generator","volume":"Volume 1841","year":"2000","journal-title":"Lecture Notes in Computer Science"},{"key":"ref_3","first-page":"348","article-title":"Iterative Probabilistic Reconstruction of RC4 Internal States","volume":"2008","author":"Golic","year":"2008","journal-title":"IACR Cryptol. ePrint Arch."},{"doi-asserted-by":"crossref","unstructured":"Paul, G., and Maitra, S. 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