1,557 research outputs found
The ElGamal cryptosystem over circulant matrices
In this paper we study extensively the discrete logarithm problem in the
group of non-singular circulant matrices. The emphasis of this study was to
find the exact parameters for the group of circulant matrices for a secure
implementation. We tabulate these parameters. We also compare the discrete
logarithm problem in the group of circulant matrices with the discrete
logarithm problem in finite fields and with the discrete logarithm problem in
the group of rational points of an elliptic curve
A New Guess-and-Determine Attack on the A5/1 Stream Cipher
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 paper, we present a new attack on the A5/1 stream cipher with an
average time complexity of 2^(48.5), which is much less than the brute-force
attack with a complexity of 2^(64). The attack has a 100% success rate and
requires about 5.65GB storage. We provide a detailed description of our new
attack along with its implementation and results.Comment: 14 pages, 4 figures, 3 table
MOR Cryptosystem and classical Chevalley groups in odd characteristic
In this paper we study the MOR cryptosystem using finite classical Chevalley
groups over a finite field of odd characteristic. In the process we develop an
algorithm for these Chevalley groups in the same spirit as the row-column
operation for special linear group. We focus our study on orthogonal and
symplectic groups. We find the hardness of the proposed MOR cryptosystem for
these groups
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