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A Hardware-Assisted Realtime Attack on A5/2 Without Precomputations.
- Source :
- Cryptographic Hardware & Embedded Systems - CHES 2007; 2007, p394-412, 19p
- Publication Year :
- 2007
-
Abstract
- A5/2 is a synchronous stream cipher that is used for protecting GSM communication. Recently, some powerful attacks [2,5] on A5/2 have been proposed. In this contribution we enhance the ciphertext-only attack [2] by Barkan, Biham, and Keller by designing special-purpose hardware for generating and solving the required systems of linear equations. For realizing the LSE solver component, we use an approach recently introduced in [5,6] describing a parallelized hardware implementation of the Gauss-Jordan algorithm. Our hardware-only attacker immediately recovers the initial secret state of A5/2 - which is sufficient for decrypting all frames of a session - using a few ciphertext frames without any precomputations and memory. More precisely, in contrast to [2] our hardware architecture directly attacks the GSM speech channel (TCH/FS and TCH/EFS). It requires 16 ciphertext frames and completes the attack in about 1 second. With minor changes also input from other GSM channels (e.g., SDCCH/8) can be used to mount the attack. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISBNs :
- 9783540747345
- Database :
- Complementary Index
- Journal :
- Cryptographic Hardware & Embedded Systems - CHES 2007
- Publication Type :
- Book
- Accession number :
- 33148456
- Full Text :
- https://doi.org/10.1007/978-3-540-74735-2_27