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Cryptanalysis of the A5/1 Stream Cipher

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dc.contributor.advisor MAHALANOBIS, AYAN en_US
dc.contributor.author SHAH, JAY en_US
dc.date.accessioned 2012-05-04T06:20:49Z
dc.date.available 2012-05-04T06:20:49Z
dc.date.issued 2012-05 en_US
dc.identifier.uri http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/170
dc.description.abstract In Europe and North America, the most widely used stream cipher to ensure privacy and confidentiality of conversations in GSM mobile phones is the A5/1. In this thesis, we study the A5/1 and some known attacks on it. We explore the weaknesses of the cipher and suggest certain modifications to the A5/1 encryption scheme with an aim to create a more secure cryptosystem resistant to most of the attacks already known. We have also designed a new attack on the A5/1 stream cipher with a minimum space complexity of around 2^(40) and an average complexity of 2^(48.5), which is much less than the brute-force attack with a complexity of 2^(64). We provide a detailed description of our new attack along with its implementation and results. Various statistical tests for randomness were performed on the suggested variants of the A5/1 which prove that these modified stream ciphers are pseudo random number generators. en_US
dc.language.iso en en_US
dc.subject 2012
dc.subject A5/1 en_US
dc.subject GSM en_US
dc.subject Guess-and-Determine attack en_US
dc.subject Stream Ciphers en_US
dc.title Cryptanalysis of the A5/1 Stream Cipher en_US
dc.type Thesis en_US
dc.type.degree BS-MS en_US
dc.contributor.department Dept. of Mathematics en_US
dc.contributor.registration 20071039 en_US


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  • MS THESES [1705]
    Thesis submitted to IISER Pune in partial fulfilment of the requirements for the BS-MS Dual Degree Programme/MSc. Programme/MS-Exit Programme

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