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In this paper, we investigate the dynamical behavior in an M-dimensional nonlinear hyperchaotic model (M-NHM), where the occurrence of multistability can be observed. Four types of coexisting attractors including single limit cycle, cluster of limit cycles, single hyperchaotic attractor, and cluster of hyperchaotic attractors can be found, which are unusual behaviors in discrete chaotic systems. Furthermore, the coexistence of asymmetric and symmetric properties can be distinguished for a given set of parameters. In the endeavor of chaotification, this work introduces a simple controller on the M-NHM, which can add one more loop in each iteration, to overcome the chaos degradation in the multistability regions.

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The complexity of a signal can be measured by the Recurrence period density entropy (RPDE) from the reconstructed phase space. We have chosen a window based RPDE method for the classification of signals, as RPDE is an average entropic measure of the whole phase space. We have observed the changes in the complexity in cardiac signals of normal healthy person (NHP) and congestive heart failure patients (CHFP). The results show that the cardiac dynamics of a healthy subject is more complex and random compare to the same for a heart failure patient, whose dynamics is more deterministic. We have constructed a general threshold to distinguish the border line between a healthy and a congestive heart failure dynamics. The results may be useful for wide range for physiological and biomedical analysis. space can be done by suitable time-delay and proper embedding dimension [6]. Suitable time-delay is generally obtained by the method of Average Mutual Information [7,8] and proper embedding dimension is obtained by method of False nearest neighbor [9−11]. However, different types of trajectory's movements have been observed in the phase space, viz; periodic, quasi-periodic, chaotic,etc, which can be described from Recurrence plot (RP) [12−16].

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Abstract. This paper presents three new attacks on the RSA cryptosystem. The first two attacks work when k RSA public keys (Ni, ei) are such that there exist k relations of the shape eix − yiφ(Ni) = zi or of the shape eixi − yφ(Ni) = zi where Ni = piqi, φ(Ni) = (pi − 1)(qi − 1) and the parameters x, xi, y, yi, zi are suitably small in terms of the prime factors of the moduli. We show that our attacks enable us to simultaneously factor the k RSA moduli Ni. The third attack works when the prime factors p and q of the modulus N = pq share an amount of their least significant bits (LSBs) in the presence of two decryption exponents d1 and d2 sharing an amount of their most significant bits (MSBs). The three attacks improve the bounds of some former attacks that make RSA insecure.

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This paper presents new short decryption exponent attacks on RSA, which successfully leads to the factorization of RSA modulus N = pq in polynomial time. The paper has two parts. In the first part, we report the usage of the small prime difference method of the form |b 2 p − a 2 q| < N γ where the ratio of. The second part of the paper reports four cryptanalytic attacks on t instances of RSA moduli N s = p s q s for s = 1, 2, . . . , t where we use N − a 2 +b 2 ab √ N + 1 as an approximation of φ(N) satisfying generalized key equations of the shape e s d s for unknown positive integers d, k s , d s , k s , and z s , where we establish that t RSA moduli can be simultaneously factored in polynomial time using combinations of simultaneous Diophantine approximations and lattice basis reduction methods. In all the reported attacks, we have found an improved short secret exponent bound, which is considered to be better than some bounds as reported in the literature.