ACHTERBAHN: A Proposal for a Profile 2 Stream Cipher to ECRYPT’s Call for Stream Cipher Primitives
نویسندگان
چکیده
We propose a new additive binary stream cipher called Achterbahn. The keystream generator (KSG) consists of eight primitive binary nonlinear feedback shift registers (NLFSR’s). A binary N -stage feedback shift register is called primitive if it has a cycle of length 2N − 1 containing all binary nonzero N tuples. Each shift register has a configurable linear feedforward output function. The output sequences of the shift registers are combined by a balanced 4thorder correlation immune Boolean combining function of eight variables and of algebraic degree three. Due to the modifiable shift register output functions, the KSG is able to produce an ensemble of 264 (respectively of 280) cyclically inequivalent sequences. All sequences have periods larger than 2207 and linear complexities larger than 285. The size of the secret key is 80 bits. The feedback functions of the driving NLFSR’s promote fast hardware implementations. In the high-speed implementation a throughput of more than 8 Gbps is reached.
منابع مشابه
Cryptanalysis of Achterbahn
We present several attacks against the Achterbahn stream cipher, which was proposed to the eSTREAM competition. We can break the reduced and the full version with complexity of 2 and 2 steps. Extensions of our attacks are also described to break modified versions of the Achterbahn stream cipher, which were proposed following the publication of preliminary cryptanalysis results. These attacks hi...
متن کاملA Stream Cipher Based on Chaotic Permutations
In this paper we introduce a word-based stream cipher consisting of a chaotic part operating as a chaotic permutation and a linear part, both of which designed on a finite field. We will show that this system can operate in both synchronized and self-synchronized modes. More specifically, we show that in the self-synchronized mode the stream cipher has a receiver operating as an unknown input o...
متن کاملImproved Boolean Combining Functions for Achterbahn
The Boolean combining function in the 80-bit-key stream cipher Achterbahn [1] is weak. Its major weakness consists of the fact that by setting two specific variables to zero, the function becomes linear. Its second weakness consists of the fact that it can be approximated by a linear function which agrees with the Boolean combining function with probability 3/4. By exploiting the first weakness...
متن کاملDesign and Primitive Specification for Shannon
1 Justification Shannon is a synchronous stream cipher with message authentication functionality, designed according to the ECrypt NoE call for stream cipher primitives, profile 1A (but well after the call). Shannon is named in memory of Claude E. Shannon[20] of Bell Labs and MIT, founder of Information Theory. Shannon is an entirely new design, influenced by members of the SOBER family of stre...
متن کامل