Weak key-IV pairs in the A5/1 stream cipher

Al Hamdan, Ali, Bartlett, Harry, Dawson, Ed , Simpson, Leonie, & Wong, Kenneth Koon-Ho (2014) Weak key-IV pairs in the A5/1 stream cipher. In Parampalli, Udaya & Welch, Ian (Eds.) Proceedings of the Twelfth Australasian Information Security Conference (AISC 2014) [Conferences in Research and Practice in Information Technology, Volume 149], Australian Computer Society, Inc., Auckland, New Zealand, pp. 23-36.

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A5/1 is a shift register based stream cipher which provides privacy for the GSM system. In this paper, we analyse the loading of the secret key and IV during the initialisation process of A5/1. We demonstrate the existence of weak key-IV pairs in the A5/1 cipher due to this loading process; these weak key-IV pairs may generate one, two or three registers containing all-zero values, which may lead in turn to weak keystream sequences. In the case where two or three registers contain only zeros, we describe a distinguisher which leads to a complete decryption of the affected messages.

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ID Code: 64105
Item Type: Conference Paper
Refereed: Yes
Additional URLs:
Keywords: A5/1, initialisation process, loading phase, weak key-IV pairs, ciphertext only attack, stream cipher
ISBN: 978-1-921770-32-6
Subjects: Australian and New Zealand Standard Research Classification > INFORMATION AND COMPUTING SCIENCES (080000) > DATA FORMAT (080400)
Australian and New Zealand Standard Research Classification > INFORMATION AND COMPUTING SCIENCES (080000) > DATA FORMAT (080400) > Data Encryption (080402)
Divisions: Current > Institutes > Institute for Future Environments
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2014 Australian Computer Society, Inc.
Copyright Statement: This paper appeared at the Australasian Information Security Conference (ACSW-AISC 2014), Auckland, New Zealand, January 2014. Conferences in Research and Practice in Information Technology (CRPIT), Vol. 149, Udaya Parampalli and Ian Welch, Ed. Reproduction for academic, not-for-profit purposes permitted provided this text is included.
Deposited On: 26 Nov 2013 01:24
Last Modified: 23 Jun 2017 14:45

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