The bit-search generator (BSG) was proposed in 2004 and can be seen as a variant of the shrinking and self-shrinking generators. It has the advantage that it works at rate 1/3 using only one LFSR and some selection logic. We present various attacks on the BSG based on the fact that the output sequence can be uniquely defined by the differential of the input sequence. By knowing only a small par...

Jansen introduced a technique for building LFSRs that can be clocked a large number of times with a single simple operation. These may be useful in the construction of stream ciphers based on clock-controlled LFSRs. However, for LFSR sizes of typical interest, it appears generally hard to find such jumping LFSRs with particular desired parameters. In this note we explain a trick which we used t...

A new form of LFSR reseedingg that provides higher encodingg efficiency andd hence greater reductionn inn test dataa storage requirements is described. Previous forms of LFSR reseedingg have beenn static (i.e., test generationn is stoppedd andd the seedd is loadedd at one time) andd have requiredd full reseedingg (i.e., n=r bits are usedd for ann r-bit LFSR). The new form of LFSR reseedingg pro...

We propose a procedure for designing an LFSRbased circuit for masking of unknown output values that appear in the output response of a circuit tested using LBIST. The procedure is based on reseeding of the LFSR to mask unknown output values while allowing fault effects to propagate. To determine the seeds, the output response of the circuit is partitioned into a minimal number of fragments, and...

In this paper we investigate nonlinear equivalence of stream ciphers over a finite field, exemplified by the pure LFSR-based filter generator over F2. We define a nonlinear equivalence class consisting of filter generators of length n that generate a binary keystream of period dividing 2−1, and investigate certain cryptographic properties of the ciphers in this class. We show that a number of i...

In this paper we demonstrate a fast correlation attack on the shrinking generator with known connections. Our attack is applicable to arbitrary weight feedback polynomial of the generating LFSR and comparisons with other known attacks show that our attack offers good trade-offs between required keystream length, success probability and complexity. Our result confirms Golić’s conjecture that the...

LILI-128 is a clock controlled stream cipher based on two LFSRs with one clock control function and one non-linear filter function. The clocking of the second LFSR is controlled by the first LFSR. In this paper we propose a fault algebraic attack on LILI-128 stream cipher. We first recover the state bits of the first LFSR by injecting a single bit fault in the first LFSR. After that we recover ...

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...

Achterbahn stream cipher is proposed as a candidate for ECRYPT eSTREAM project which deals with key of length 80-bit. The linear distinguishing attack,which aims at distinguishing the keystream from purely random keystream,is employed to Achterbahn stream cipher. A linear distinguishing attack is based on linear sequential circuit approximation technique which distinguishes statistical bias in ...

In this paper, we describe a solution to the register synthesis problem for a class of sequence generators known as Algebraic Feedback Shift Registers. These registers are based on the algebra of π-adic numbers, where π is an element in a ring R, and produce sequences of elements in R/(π). We give several cases where the register synthesis problem can be solved by an efficient algorithm. Conseq...