A new version of the stream cipher Grain-128 is proposed. The new version, Grain-128a, is strengthened against all known attacks and observations on the original Grain-128, and has built-in support for optional authentication. The changes are modest, keeping the basic structure of Grain-128. This gives a high confidence in Grain-128a and allows for easy updating of existing implementations.

It is necessary that the linear complexity of a key stream sequence in a stream cipher system is not less than half of a period. This paper puts forward the linear complexity of a class of binary interleaved sequences with period 4N over the finite field with characteristic 2. Results show that the linear complexity of some of these sequences satisfies the requirements of cryptography.

In this paper we investigate univariate algebraic attacks on filter generators over extension fields Fq = F2n with focus on the WelchGong (WG) family of stream ciphers. Our main contribution is to break WG-5, WG-7, WG-8 and WG-16 by combining results on the so-called spectral immunity (minimum distance of certain cyclic codes) with properties of the WG type stream cipher construction. The spect...

Pomaranch [3] is a synchronous stream cipher submitted to eSTREAM, the ECRYPT Stream Cipher Project. The cipher is constructed as a cascade clock control sequence generator, which is based on the notion of jump registers. In this paper we present an attack which exploits the cipher's initialization procedure to recover the 128-bit secret key. The attack requires around 2 computations. An improv...

8th Central European Conference on Cryptography 2008 1 Let’s call ECC-box a coponent which encodes the plaintext in order to provide correction of the random errors. Note that in the proposing stream cipher ECC-box encodes the plaintext so that it can be recovered correctly after corruption by the errors introduced in the ciphertext deliberately. Block scheme of the novel stream cipher family i...