The length based attack on Anshel-Anshel-Goldfeld commu-tator key-exchange protocol  was initially proposed by Hughes and Tannenbaum in . Several attempts have been made to implement the attack , but none of them had produced results convincing enough to believe that attack works. In this paper we show that accurately designed length based attack… (More)
The Anshel-Anshel-Goldfeld-Lemieux (abbreviated AAGL) key agreement protocol  is proposed to be used on low-cost platforms which constraint the use of computational resources. The core of the protocol is the concept of an Algebraic Eraser T M (abbreviated AE) which is claimed to be a suitable primitive for use within lightweight cryptography. The AE… (More)
We propose a polynomial time quantum algorithm for solving the discrete logarithm problem in matrices over finite group rings. The hardness of this problem was recently employed in the design of a key-exchange protocol proposed by D. Kahrobaei, C. Koupparis, and V. Shpilrain . Our result implies that the Kahrobaei et al. protocol does not belong to the… (More)
This article is a short introduction to generic case complexity, which is a recently developed way of measuring the difficulty of a computational problem while ignoring atypical behavior on a small set of inputs. Generic case complexity applies to both recursively solvable and recursively unsolvable problems.
The goal of this paper is to introduce ideas and methodology of the generic case complexity to cryptography community. This relatively new approach allows one to analyze the behavior of an algorithm on " most " inputs in a simple and intuitive fashion which has some practical advantages over classical methods based on averaging. We present an alternative… (More)
In this paper we cryptanalyze two protocols: Grigoriev-Shpilrain authentication protocol and Wang et al. public key encryption protocols that use computational hardness of some variations of the conjugacy search problem in noncommutative monoids. We devise a practical heuristic algorithm solving those problems. As a conclusion we claim that these protocols… (More)