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dc.contributor.author許亨仰en_US
dc.contributor.authorXu, Heng-Yangen_US
dc.contributor.author張文輝en_US
dc.contributor.authorZhang, Wen-Huien_US
dc.date.accessioned2014-12-12T02:19:46Z-
dc.date.available2014-12-12T02:19:46Z-
dc.date.issued1997en_US
dc.identifier.urihttp://140.113.39.130/cdrfb3/record/nctu/#NT864435001en_US
dc.identifier.urihttp://hdl.handle.net/11536/63640-
dc.description.abstractExtensive eavesdropping on phone extensions necessitates the development ofan end-to-end secure communication. Most commercial speech security equipmentsapply the analog scrambling technique, particularly the frequency-domain scramblerwhich derives its cryptanalytic strength from random permutation of speech spectrum.Since in most systems the security resides in the permutation (the key), it is worthdiscussing the processing of deducing correct key from insufficiently scrambled speech. A brute force attack requires an exhaustive search over the entire discretekeyspace and is obviously impractical. To overcome this problem, we propose an automated cryptanalysis approach in which the key search is realized in the maximum likelihood estimation process. For greater efficiency, this task can be formulated as one of the perfect matching problems that leads to search for the permutation associated the minimum cost. In the proposed system, we use the genetic algorithm to find the global optimal solution. As compared with Baum's iterative maximization algorithm, the genetic-based search is shown to yield better performance by taking into account the doubly stochastic constraint of the underlying keyspace.zh_TW
dc.language.isozh_TWen_US
dc.subject解密zh_TW
dc.subject混音系統zh_TW
dc.subject基因法則zh_TW
dc.subject類比混音器zh_TW
dc.subject數位加密器zh_TW
dc.subject自動化解密zh_TW
dc.subject頻域混音器zh_TW
dc.subject遺傳演算法zh_TW
dc.subject電信zh_TW
dc.subject電子工程zh_TW
dc.subjectcryptanalysisen_US
dc.subjectscrambleren_US
dc.subjectgenetic algorithmen_US
dc.subjectAnalog scrambleren_US
dc.subjectAutomated cryptanalysisen_US
dc.subjectFrequency-domain scrambleren_US
dc.subjectGenetic algorithmen_US
dc.subjectTELECOMMUNICATIONen_US
dc.subjectELECTRONIC-ENGINEERINGen_US
dc.title頻域混音系統的自動化解密研究zh_TW
dc.titleAutomated Cryptanalysis of Frequency-Domain Speech Scramblersen_US
dc.typeThesisen_US
dc.contributor.department電信工程研究所zh_TW
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