Abstract: The origins of eSTREAM can be traced back to the 2004 RSA Data Security Conference There, as part of the Cryptographer's Panel, Adi Shamir made some insightful comments on the state of stream ciphers In particular, with AES [8] deployment being so wide-spread, Shamir wondered whether there remained a need for a stream cipher of dedicated design As arguments against, one might observe that for most applications, the use of the AES in an appropriate stream cipher mode [9] frequently offers a perfectly adequate solution Some also doubt our understanding of how best to design a dedicated stream cipher, a view somewhat supported by the lack of surviving stream ciphers in the NESSIE project [1] However, as counter-arguments Shamir went on to identify two areas where a dedicated stream cipher might conceivably offer some advantage over block ciphers: (1) where exceptionally high throughput is required in software and (2) where exceptionally low resource consumption is required in hardware

Abstract: Recently, Pareek et al. proposed a symmetric key block cipher using multiple one-dimensional chaotic maps. This paper reports some new findings on the security problems of this kind of chaotic cipher: (1) a number of weak keys exist; (2) some important intermediate data of the cipher are not sufficiently random; (3) the whole secret key can be broken by a known-plaintext attack with only 120 consecutive known plain-bytes in one known plaintext. In addition, it is pointed out that an improved version of the chaotic cipher proposed by Wei et al. still suffers from all the same security defects.

Abstract: The stream cipher Rabbit was first presented at FSE 2003 [3], and no attacks against it have been published until now. With a measured encryption/decryption speed of 3.7 clock cycles per byte on a Pentium III processor, Rabbit does also provide very high performance. This paper gives a concise description of the Rabbit design and some of the cryptanalytic results available.

Abstract: We present a design approach for hardware-oriented self-synchronizing stream ciphers and illustrate it with a concrete design called Moustique . The latter is intended as a research cipher: it proves that the design approach can lead to concrete results and will serve as a target for cryptanalysis where new attacks may lead to improvements in the design approach such as new criteria for the cipher building blocks.

Abstract: SMS4 is a 128-bit block cipher used in the WAPI standard. WAPI is the Chinese national standard for securing Wireless LANs. Since the specification of SMS4 was not released until January 2006, there have been only a few papers analyzing this cipher. In this paper, firstly we present a kind of 5-round iterative differential characteristic of SMS4 whose probability is about 2? 42. Then based on this kind of iterative differential characteristic, we present a rectangle attack on 16-round SMS4 and a differential attack on 21-round SMS4. As far as we know, these are the best cryptanalytic results on SMS4.

Abstract: This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a number of secret keys invalid; (2) It is insensitive to the change of the secret key; (3) It is insensitive to the change of the plain-image; (4) It can be broken with only one known/chosen plaintext; (5) It has some other minor defects. The proposed cryptanalysis discourages any use of the scheme in practice.

Abstract: SMS4 is a 128-bit block cipher with a 128-bit user key and 32 rounds, which is used in WAPI, the Chinese WLAN national standard. In this paper, we present a linear attack and a differential attack on a 22round reduced SMS4; our 22-round linear attack has a data complexity of 2 known plaintexts, a memory complexity of 2 bytes and a time complexity of 2 22-round SMS4 encryptions and 2 arithmetic operations, while our 22-round differential attack requires 2 chosen plaintexts, 2 memory bytes and 2 22-round SMS4 encryptions. Both of our attacks are better than any previously known cryptanalytic results on SMS4 in terms of the number of attacked rounds. Furthermore, we present a boomerang and a rectangle attacks on a 18-round reduced SMS4. These results are better than previously known rectangle attacks on reduced SMS4. The methods presented to attack SMS4 can be applied to other unbalanced Feistel ciphers with incomplete diffusion.

Abstract: A modification of the Hill cipher algorithm was recently proposed by Ismail et al. (2006), who claimed that their new scheme could offer more security than the original one due to an extra non-linearity layer introduced via an elaborated key generation mechanism. That mechanism produces one different encryption key for each one of the plaintext blocks. Nevertheless, we show in this paper that their method still has severe security flaws whose weaknesses are essentially the same as that already found in the original Hill cipher scheme.

Abstract: Block ciphers based on key-dependent cipher structures have been investigated for years, however, their overall performance in terms of security and speed has not been sufficiently addressed. In this paper, we propose a 128-bit Feistel block cipher, which simultaneously engages key-dependent S-box and key-dependent P-box. With these two key-dependent transformations, the internal structure of this cipher algorithm is secured, so as to resist the linear and differential cryptanalysis in a few round encryptions. Hence, the encryption and decryption functions are quite efficiency. We named this key-dependent structure the DSDP structure, and the cipher DSDP. A fast permutation algorithm is used to generate both the key-dependent S-box and key-dependent P-boxes. This greatly compensates the performance penalty of complex key schedule. The basic operations used in DSDP are all efficient bytewise operations, so the algorithm will have a reasonable fast speed on recent processors, 16-bit processors and smart cards as well as 8-bit processors. We implement the algorithm with C and Java respectively on several PCs with different processors, and estimate the optimized assembly performance on Pentium. The experimental results and the estimation show that DSDP has a very fast encryption/decryption speed and a reasonable fast key scheduling implementation.

Abstract: Among recent developments on stream ciphers, the algebraic attack has gained much attention In this paper we concentrate on algebraic cryptanalysis of Grain, a non-linear feedback shift register (NLFSR) based stream cipher The target here is to analyze generic key generating structure of Grain, that is why, we aim to recover the internal states of cipher rather than the key-bits Experiments are carried out to solve these varying degree equations, with some guessed bits using Groebner basis technique Our approach succeeds in recovering (approx) 1/2 of the internal stateAmong recent developments on stream ciphers, the algebraic attack has gained much attention In this paper we concentrate on algebraic cryptanalysis of Grain, a non-linear feedback shift register (NLFSR) based stream cipher The target here is to analyze generic key generating structure of Grain, that is why, we aim to recover the internal states of cipher rather than the key-bits Experiments are carried out to solve these varying degree equations, with some guessed bits using Groebner basis technique Our approach succeeds in recovering (approx) 1/2 of the internal state bits of Grain-1, while other half are guessed While, in case of Grain-128, only 1/4 of the state bits can be obtained bits of Grain-1, while other half are guessed While, in case of Grain-128, only 1/4 of the state bits can be obtained

Abstract: In this paper we define a notion of leak extraction from a block cipher. We demonstrate this new concept on an example of AES. A result is LEX: a simple AES-based stream cipher which is at least 2.5 times faster than AES both in software and in hardware.

Abstract: Disclosed is the design and development of a new cipher called the Dragonfire Cipher. The Dragon cipher includes message authentication code and keyed random number generator. Dragonfire cipher takes this transparent method of generating S-boxes and uses them to create a cipher with keyed S-boxes. This defeats most precomputations for cryptanalysis as the S-boxes are now different between sessions.

Abstract: We propose a scalable block cipher which is an involutional SPN. We use one S-box which is an involution and a bit permutation which also is an involution. As a result we received a totally involutional cipher. It means that we use the same network, and especially the same S-box and the same permutation P in the encryption and decryption data processing. PP-1 is a symmetric block cipher designed for platforms with very limited resources, especially with restricted amount of memory needed to store its components.

Abstract: This paper presents a block cipher based on private key to be implemented in bit-level. The scheme used in the proposed cipher is substitutionbased. Encryption through this proposed cipher also results in possible lossless compression. Efficiencies of the proposed cipher are observed and compared with the existing cipher IDEA on execution time, rate of compression achieved and chi-square value. Graphically frequency-distribution of characters in source and corresponding encrypted file are observed for a sample file. On the basis of all observations made, proposed cipher is found to be efficient. Requirements of key space of least 166-bit makes it invulnerable to attacks. It is highly compatible with existing cipher like IDEA.

Abstract: In this research, we have developed a large block cipher by modifying the Hill cipher. In this, we have introduced interlacing of the binary bits of the plaintext as the primary concept leading to confusion. This process is strengthened by using iteration. The cryptanalysis and avalanche effect mentioned in this research clearly exhibit the strength of the cipher.

Abstract: In this paper, we propose a LDPC error correcting cipher which joints the Advanced Encryption Standard (AES) and LDPC code together. The LDPC error correcting cipher which is based on the wide trail strategy is a six round block cipher that encrypts 256 bit plaintexts using secret key to produce 512 bit ciphertexts, and the key is composed of 128 bit AES secret key and LDPC generator matrix. By using the LDPC generator matrix with high performance in diffusion property, we made the LDPC error correcting cipher as secure as the Advanced Encryption Standard (AES) against linear, differential attacks in fewer rounds. Even the square attack has no effect on attacking the cipher. Lastly, the process of encrypting/decrypting is implemented, and the security and error correction capacity is analyzed also.

Abstract: CryptMT version 3 (CryptMT3) is a stream cipher obtained by combining a large LFSR and a nonlinear filter with memory using integer multiplication. Its period is proved to be no less than 219937? 1, and the 8-bit output sequence is at least 1241-dimensionally equidistributed. It is one of the fastest stream ciphers on a CPU with SIMD operations, such as Intel Core 2 Duo.

Abstract: Block ciphers based on key-dependent cipher structures have been investigated for years, however, their overall performance in terms of security and key-setup speed has not been sufficiently addressed. In this paper, we propose a 128-bit block cipher based on a novel SPN structure, which uses both S-box and P-boxes that are all key-dependent. With these two key-dependent transformations, the internal structure of this cipher algorithm is hided from the cryptanalyst, so as to resist the linear and differential cryptanalysis in a few round encryptions. We named this key-dependent structure the DSDP structure, and the cipher DSDP. A fast permutation algorithm is used to generate both the key-dependent S-box and key-dependent P-boxes. This greatly compensates the performance penalty of complex key schedule. The experimental results show that our algorithm has a very fast encryption/decryption speed and a reasonable fast key scheduling implementation.

Abstract: The Hill cipher algorithm is one of the symmetric key algorithms that have several advantages in data encryption. However, a drawback of this algorithm is that the inverse of the matrix used for encrypting the plaintext does not always exist. So, if the matrix is not invertible, the encrypted text cannot be decrypted. This paper presents a variant of the Hill cipher that overcomes this disadvantage. The proposed technique adjusts the encryption key to form a different key for each block encryption. The proposed variant yields higher security compared to the original one. Also in this paper, a method of generating self-invertible matrix for Hill Cipher algorithm has been proposed. In the self-invertible matrix generation method, the matrix used for the encryption is itself self-invertible. So, at the time of decryption, we need not to find inverse of the matrix. Moreover, this method eliminates the computational complexity involved in finding inverse of the matrix while decryption.

Abstract: In this paper, we present a new implementation of the WG stream cipher for data security in communications. The implementation is based on the interleaved approach with precomputation only the WG transformation sequence and precomputation of shift sequence is not required. It works 8 times faster than known implementation of the WG stream cipher proposed by Nawaz and Gong. The new implementation requires storage for saving of the WG transformation sequence but it is more simple in development because all computations are carried out by modulo 2.

Abstract: Matrix cryptosystems, like Hill cipher, are resistant to frequency analysis. The key is a non-singular k times k matrix, for example 3 times 3 matrix K. In this paper, we propose simple criteria to generate a modular non-singular key-matrix for matrix ciphers fast. We apply these results to cryptography and computer security. In this paper, we present a mutualauthentication protocol based on Hamiltonian cycle in directed weight graphs and modular matrix algebra.

Abstract: In this paper, we present a new tweakable narrow-block mode of operation, the Substitution Cipher Chaining mode (SCC), that can be efficiently deployed in disk encryption applications. SCC is characterized by its high throughout compared to the current solutions and it can be parallelized. We used this mode to modify Windows Vista’s disk encryption algorithm, to offer some parallelism in its original implementation and to improve its diffusion properties.

Abstract: This paper presents a substitution-based block cipher that considers a file to be encrypted as a bit-stream. The cipher implements a storage efficient algorithm through which along with encryption a reduction in size is also achieved. As encryption is done at bit label, this algorithm can be implemented on any kind of files. A tendency of increase in execution time is observed. The proposed technique is compared with the existing International Data Encryption Algorithm (IDEA) with respect to execution time and degree of nonhomogeneity. A generalized expression for the key space is formularized.

Abstract: Dragon is a word-based stream cipher. It was submitted to the eSTREAM project in 2005 and has advanced to Phase 3 of the software profile. This paper discusses the Dragon cipher from three perspectives: design, security analysis and implementation. The design of the cipher incorporates a single word-based non-linear feedback shift register and a non-linear filter function with memory. This state is initialized with 128- or 256-bit key-IV pairs. Each clock of the stream cipher produces 64 bits of keystream, using simple operations on 32-bit words. This provides the cipher with a high degree of efficiency in a wide variety of environments, making it highly competitive relative to other symmetric ciphers. The components of Dragon were designed to resist all known attacks. Although the design has been open to public scrutiny for several years, the only published attacks to date are distinguishing attacks which require keystream lengths greatly exceeding the stated 264bit maximum permitted keystream length for a single key-IV pair.

Abstract: In cryptography technology,random sequence is very important,and the randomness test of sequence is always an important subject in information security.For the shortcomings of current randomness test system,a randomness test system is researched and de-signed in Visual C++.NET.According to the difference between stream cipher and block cipher,the system tests separately.In stream cipher,a new kind of partition and organization method of test sequence is given,while in block cipher,three data mode are designed to build sequence that will be tested.The system is tested strictly,and it is proved that the system can test randomness of stream cipher,block cipher and random number generator quickly and accurately.

Abstract: Several Genetic Algorithms have been developed for applications of cryptography problem; the primary distinction among all of them being the G.A. used for decryption problem and obtains the plain text. In this paper a new approach is proposed using Genetic Algorithm with cryptography. G.A. is used to obtain a best secret key in polyalphabetic substitution cipher. This key will be used then for encryption and decryption with a high level of security. The program is written in Matlab language (6.5).

Abstract: DSP-128 is a new multithreaded stream cipher based on the intractability of the Discrete Logarithm Problem (DLP) with key size of 128-bit. The design of DSP-128 is divided into three stages: Initialization Stage, Keystream Generation Stage, and Encryption Stage. The design goal of DSP-128 is to come up with a secure stream cipher with good performance for data encryption. The experimental results show that the encryption rate of DSP-128 is one time slower (running on single processor) than the widely adapted stream cipher RC4, with a higher level of security against possible cryptanalysis attacks. However, because of its multithreaded nature, DSP-128 can take the speed up advantage of multi-core processor architectures which are available widely.