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Ayan Mahalanobis

Publications and source records attributed to Ayan Mahalanobis.

27 records · Page 2Linked to original sources
arXiv2012

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.

cs.CR↗
arXiv2011

The MOR cryptosystem and extra-special $p$-groups

This paper studies the MOR cryptosystem, using the automorphism group of the extra-special $p$-group of exponent $p$, for an odd prime $p$. Similar results can be obtained for extra-special $p$-groups of exponent $p^2$ and for the even prime.

math.GR↗
arXiv2011

A simple generalization of the ElGamal cryptosystem to non-abelian groups II

This is a study of the MOR cryptosystem using the special linear group over finite fields. The automorphism group of the special linear group is analyzed for this purpose. At our current state of knowledge, I show that the MOR cryptosystem has better security than the ElGamal cryptosystem over finite fields.

cs.CR↗
arXiv2007

The Diffie-Hellman Key Exchange Protocol and non-abelian nilpotent groups

In this paper we study a key exchange protocol similar to Diffie-Hellman key exchange protocol using abelian subgroups of the automorphism group of a non-abelian nilpotent group. We also generalize group no.92 of Hall-Senior table \cite{halltable}, for arbitrary prime $p$ and show that for those groups, the group of central automorphisms commute. We use these for the key exchange we are studying.

math.GR↗
arXiv2007

A simple generalization of El-Gamal cryptosystem to non-abelian groups

In this paper we study the MOR cryptosystem. We use the group of unitriangular matrices over a finite field as the non-abelian group in the MOR cryptosystem. We show that a cryptosystem similar to the El-Gamal cryptosystem over finite fields can be built using the proposed groups and a set of automorphisms of these groups. We also show that the security of this proposed MOR cryptosystem is equivalent to the El-Gamal cryptosystem over finite fields.

cs.CR↗
arXiv2007

A note on using finite non-abelian $p$-groups in the MOR cryptosystem

The MOR cryptosystem is a natural generalization of the El-Gamal cryptosystem to non-abelian groups. Using a $p$-group, a cryptosystem was built by this author in 'A simple generalization of El-Gamal cryptosystem to non-abelian groups'. It seems reasonable to assume the cryptosystem is as secure as the El-Gamal cryptosystem over finite fields. A natural question arises can one make a better cryptosystem using $p$-groups? In this paper we show that the answer is no.

cs.CR↗