Complexity measures for sequences over finite fields, such as the linear complexity and the k-error linear complexity, play an important role in cryptology. Recent developments in stream ciphers point towards an interest in word-based stream ciphers, which require the study of the complexity of multisequences. We introduce various options for error linear complexity measures for multisequences....

The purpose of algebraic attacks on stream and block ciphers is to recover the secret key by solving an overdefined system of multivariate algebraic equations. They become very efficient if this system is of low degree. In particular, they have been used to break stream ciphers immune to all previously known attacks. This kind of attack tends to work when certain Boolean functions used in the c...

Efficient cryptographic implementations are a fundamental factor in the achievement and dissemination of new computerized applications. In some recent environments with (very) limited resources such as smart cards, sensor networks or RFID tags, standard algorithms may not be completely adapted.Consequently, the design of new solutions for low-cost cryptography is sometimes necessary and is at l...

Stream ciphers are often used in applications where high speed and low delay are a requirement. The Solitaire stream cipher was developed by B. Schneier as a paper-and-pencil cipher. Solitaire gets its security from the inherent randomness in a shuffled deck of cards. In this paper we investigate semigroups and groups properties of the Solitaire stream cipher and its regular modiÞcations.

In this paper, we introduce the rakaposhi stream cipher. The algorithm is based on Dynamic Linear Feedback Shift Registers, with a simple and potentially scalable design, and is particularly suitable for hardware applications with restricted resources. The rakaposhi stream cipher offers 128-bit security, and aims to complement the current eSTREAM portfolio of hardware-oriented stream ciphers.

In this article, we present a new code-based stream cipher called 2SC, based on the sponge construction. The security of the keystream generation of 2SC is reducible to the conjectured intractability of the Syndrome Decoding (SD) problem, which is believed to be hard in the average case. Our stream cipher compares favorably with other provably secure stream ciphers such as QUAD and SYND in term...

In this paper we design a stream cipher that uses the algebraic structure of the multiplicative group Z Z * p (where p is a big prime number used in ElGamal algorithm), by defining a quasigroup of order p − 1 and by doing quasigroup string transformations. The cryptograph-ical strength of the proposed stream cipher is based on the fact that breaking it would be at least as hard as solving syste...

Abstract. A T-function is a mapping from n-bit words to n-bit words in which for each 0 ≤ i < n, bit i of any output word can depend only on bits 0, 1, . . . , i of any input word. All the boolean operations and most of the numeric operations in modern processors are T-functions, and all their compositions are also T-functions. Our earlier papers on the subject dealt with “crazy” T-functions wh...

In this paper, we introduce a new class of PRSGs, called partitioned pseudorandom sequence generators(PPRSGs), and propose an RFID authentication protocol using a PPRSG, called S-protocol. Since most existing stream ciphers can be regarded as secure PPRSGs, and stream ciphers outperform other types of symmetric key primitives such as block ciphers and hash functions in terms of power, performan...

For security applications in wireless sensor networks (WSNs), choosing best algorithms in terms of energy-efficiency and of small-storage requirements is a real challenge because the sensor networks must be autonomous. In [22], the authors have benchmarked on a dedicated platform some block-ciphers using several modes of operations and have deduced the best block cipher to use in the context of...