In 1985 Siegenthaler introduced the concept of correlation attacks on LFSR based stream ciphers. A few years later Meier and Staffelbach demonstrated a special technique, usually referred to as fast correlation attacks, that is very effective if the feedback polynomial has a special form, namely, if its weight is very low. Due to this seminal result, it is a well known fact that one avoids low ...

In this paper, we present Decim, a stream cipher hardwareoriented selected for the phase 3 of the ECRYPT stream cipher project eSTREAM. As required by the initial call for hardware-oriented stream cipher contribution, Decim manages 80-bit secret keys and 64-bit public initialization vectors. The design of Decim combines two filtering mechanisms: a nonlinear Boolean filter over a LFSR, followed ...

We present a new design for random number generation. The outputs of linear feedback shift registers (LFSRs) act as continuous inputs to the two boundaries of a one-dimensional (1-D) Elementary Cellular Automata (ECA). The results show superior randomness features and the output string has passed the Diehard statistical battery of tests. The design is good candidate for parallel random number g...

A linear feedback shift register (LFSR) is the basic element of pseudo-random generators used to generate a sequence values for stream cipher. It consists several cells; each cell flip-flop and function. The function polynomial function; this has degree equal number cells in register. elements are connected other two different ways, either Fibonacci mode or Galois mode. In work, we propose real...

Let q be a prime power and Fq be the finite field with q elements. A q-ary m-sequence is a linear recurrence sequence of elements from Fq with the maximum possible period. A covering array CA(N ; t, k, v) of strength t is a N ×k array with entries from an alphabet of size v, with the property that any N×m subarray has at least one row equal to every possible m-tuple of the alphabet. The coverin...

In this work, a wide family of LFSR-based sequence generators, the so-called Clock-Controlled Shrinking Generators (CCSGs), has been analyzed and identified with a subset of linear Cellular Automata (CA). In fact, a pair of linear models describing the behavior of the CCSGs can be derived. The algorithm that converts a given CCSG into a CA-based linear model is very simple and can be applied to...

In this paper, we prove the probability advantages of two linear expressions which are summarized from the ABC stream cipher submitted to ECRPYT Estream Project. Two linear expressions with probability advantages reflect the linear correlations among Modular Addition equations. Corresponding to each linear expression and its advantage, a large amount of weak keys are derived under which all the...

The linear complexity of the Generalized Shrinking-Multiplexing Generator (GSMG), based on Linear Shift Feedback Registers (LFSRs), is investigated in this paper. The lower and upper bounds of linear complexity of its output binary Pseudo Random Sequences are established. It is proved that the linear complexity increases exponentially with the length of the control p-ary LFSR and the prime p us...

We present a realization of an LFSM that utilizes an LFSR. This is based on a well-known fact from linear algebra. This structure is used to show that a previous attempt at using a CA in place of an LFSR in constructing a stream cipher did not necessarily increase its security. We also give a general method for checking whether or not a nonlinear filter generator based on an LFSM allows reducti...