In this paper we consider an attack on the SIGABA cipher under the assumption that the largest practical keyspace is used. The attack highlights various strengths and weaknesses of SIGABA and provides insight into the inherent level of security provided by the cipher.

This paper develops a new algorithm to improve the security of RC4. Given that RC4 cipher is widely used in the wireless communication and has some weaknesses in the security of RC4 cipher, our idea is based on the combination of the RC4 and the poly alphabetic cipher Vigenère to give a new and more secure algorithm which we called VRC4. In this technique the plain text is encrypted using the c...

Is it possible that a block cipher apparently immune to classical differential cryptanalysis can be attacked considering a different operation on the message space? Recently Calderini and Sala showed how to effectively compute alternative operations on a vector space which can serve as message space for a block cipher such that the resulting structure is still a vector space. The latter were us...

At IEEE GLOBECOM 2008, a lightweight cipher based on a Multiple Recursive Generator (MRG) was proposed for use in resource limited environment such as sensor nodes and RFID tags. This paper proposes two efficient attacks on this MRG cipher. A distinguishing attack is firstly introduced to identify the use of an MRG cipher that has a modulus suggested by its designers. It requires 218 words of c...

In this paper we introduce a new method of attacks on block ciphers, the interpolation attack. This new method is useful for attacking ciphers using simple algebraic functions (in particular quadratic functions) as S-boxes. Also, ciphers of low non-linear order are vulnerable to attacks based on higher order diierentials. Recently, Knudsen and Nyberg presented a 6-round prototype cipher which i...

In this investigation, we have developed an unbreakable block cipher with extended play color cipher algorithm. This includes multiple transpositions, substitutions, modular arithmetic, integral functions and a 32 characters alphanumeric key. These functions mutate the plain text in various ways before it takes the shape of cipher text. The process of encryption, decryption and the sub key gene...

Interpolation attack was presented by Jakobsen and Knudsen at FSE’97. Interpolation attack is effective against ciphers that have a certain algebraic structure like the PURE cipher which is a prototype cipher, but it is difficult to apply the attack to real-world ciphers. This difficulty is due to the difficulty of deriving a low degree polynomial relation between ciphertexts and plaintexts. In...

In this paper, we present a correlation attack on Sosemanuk with complexity less than 2. Sosemanuk is a software oriented stream cipher proposed by Berbain et al. to the eSTREAM call for stream cipher and has been selected in the final portfolio. Sosemanuk consists of a linear feedback shift register(LFSR) of ten 32-bit words and a finite state machine(FSM) of two 32-bit words. By combining lin...

s of invited lectures Extended differential properties of cryptographic functions ANNE CANTEAUT (INRIA-Rocquencournt, France) Differential cryptanalysis is one of the very first attack proposed against block ciphers. This attack exploits the fact that some derivatives of the cipher (or of a reduced version of the cipher) have a nonrandom output distribution. Since this distribution highly depen...

Table 3. Complexity of the attack by the size of the known plaintext and any other le which is encrypted by the same key. This known plaintext attack breaks the cipher using 40 (compressed) known plaintext bytes, or about the 200 rst uncompressed bytes (if the le is compressed), with complexity 2 34. Using about 10000 known plaintext bytes, the complexity is reduced to about 2 27. Table 3 descr...