We study how to construct efficient tweakable block ciphers in the Random Permutation model, where all parties have access to public random permutation oracles. We propose a construction that combines, more efficiently than by mere black-box composition, the CLRW construction (which turns a traditional block cipher into a tweakable block cipher) of Landecker et al. (CRYPTO 2012) and the iterate...

Mansour Mesdaghi was born in 1941 in Ghazvin, Iran, where he completed his elementary and high school.After graduation from Gorgan Forest and Range school, he had been employed in Ministry of Natural Resources as a technician in FAO branch of United Nation in collaboration with Dr. D. L. Goodwin, the Range Scientist at Houmand Range Research Station. He received his B.A degree in Economics at T...

Recent results by Alagic and Russell have given some evidence that the Even-Mansour cipher may be secure against quantum adversaries with quantum queries, if considered over other groups than (Z/2)n. This prompts the question as to whether or not other classical schemes may be generalized to arbitrary groups and whether classical results still apply to those generalized schemes. In this thesis,...

The Even-Mansour cipher is a simple method for constructing (keyed) pseudorandom permutation E from public random $$P:\{0,1\}^n \rightarrow \{0,1\}^n$$ . It secure against classical attacks, with optimal attacks requiring $$q_E$$ queries to and $$q_P$$ P such that $$q_E \cdot q_P \approx 2^n$$ If the attacker given quantum access both P, however, completely insecure, using $$q_E, = O(n)$$ known...

In [1] a construction of a block cipher from a single pseudorandom permutation is proposed. In a complexity theoretical setting they prove that this scheme is secure against a polynomially bounded adversary. In this paper it is shown that this construction suffers from severe limitations that are immediately apparent if differential cryptanalysis [3] is performed. The fact that these limitation...

Since the beginning of the last two decades, many researchers have been involved in the problem of Blind Source Separation (BSS). Whilst hundreds of algorithms have been proposed to solve BSS. These algorithms are well known as Independent Component Analysis (ICA) algorithms. Nowadays, ICA algorithms have been used to deal with various applications and they are using many performance indices. T...

The iterated Even-Mansour construction defines a block cipher from a tuple of public n-bit permutations (P1, . . . , Pr) by alternatively xoring some n-bit round key ki, i = 0, . . . , r, and applying permutation Pi to the state. The tweakable Even-Mansour construction generalizes the conventional Even-Mansour construction by replacing the n-bit round keys by n-bit strings derived from a master...

In this paper we consider the following fundamental problem: What is the simplest possible construction of a block cipher which is provably secure in some formal sense? This problem motivated Even and Mansour to develop their scheme in 1991, but its exact security remained open for more than 20 years in the sense that the lower bound proof considered known plaintexts, whereas the best published...