Comparison analysis of stream cipher algorithms for digital communication

The broadcast nature of radio communication such as in the HF (High Frequency) spectrum exposes the transmitted information to unauthorized third parties. Confidentiality is ensured by employing cipher system. For bulk transmission of data, stream ciphers are ideal choices over block ciphers due to faster implementation speed and not introducing error propagation. The stream cipher algorithms evaluated are based on the linear feedback shift register (LFSR) with nonlinear combining function. By using a common key length and worst case conditions, the strength of several stream cipher algorithms are evaluated using statistical tests, correlation attack, linear complexity profile and nonstandard test. The best algorithm is the one that exceeds all of the tests

Error linear complexity measures for multisequences

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. For finite multisequences as well as for periodic multisequences with prime period, we present formulas for the number of multisequences with given error linear complexity for several cases, and we present lower bounds for the expected error linear complexity

A New Type of Cipher: DICING_csb

In this paper, we will propose a new type of cipher named DICING_csb, which is derived from our previous stream cipher DICING. It has applied a stream of subkey and an encryption form of block ciphers, so it may be viewed as a combinative of stream cipher and block cipher. Hence, the new type of cipher has fast rate like a stream cipher and need no MAC.Comment: There is a new variant added in the section

Grein. A New Non-Linear Cryptoprimitive

In this thesis, we will study a new stream cipher, Grein, and a new cryptoprimitive used in this cipher. The second chapter gives a brief introduction to cryptography in general. The third chapter looks at stream ciphers in general, and explains the advantages and disadvantages of stream ciphers compared to block ciphers. In the fourth chapter the most important building blocks used in stream ciphers are explained. The reader is excepted to know elementary abstract algebra, as much of the results in this chapter depend on it. In the fifth chapter, the stream cipher Grain is introduced. In chapter six, the new stream cipher, Grein, is introduced. Here, we look at the different components used in the cipher, and how they operate together. In chapter seven, we introduce an alteration to the Grein cryptosystem, which hopefully have some advantagesMaster i InformatikkMAMN-INFINF39

Self-synchronizing stream ciphers and dynamical systems: state of the art and open issues

International audienceDynamical systems play a central role in the design of symmetric cryptosystems. Their use has been widely investigated both in ''chaos-based'' private communications and in stream ciphers over finite fields. In the former case, they get the form of automata named as Moore or Mealy machines. The main charateristic of stream ciphers lies in that they require synchronization of complex sequences generated by the dynamical systems involved at the transmitter and the receiver part. In this paper, we focus on a special class of symmetric ciphers, namely the Self-Synchronizing Stream Ciphers. Indeed, such ciphers have not been seriously explored so far although they get interesting properties of synchronization which could make them very appealing in practice. We review and compare different design approaches which have been proposed in the open literature and fully-specified algorithms are detailed for illustration purpose. Open issues related to the validation and the implementation of Self-Synchronizing Stream Ciphers are developped. We highlight the reason why some concepts borrowed from control theory appear to be useful to this end

The mathematical models of modernstream ciphers

Дана робота присвячена аналізу сучасних потокових шифрів, а також методиці оцінювання поточних шифрів за наступними критеріями: шифрування довгих повідомлень, шифрування коротких повідомлень, ініціалізація / генерація ключових параметрів.This paper devoted to the analysis of modern stream ciphers and methods of evaluation of stream ciphers on the following criteria: encrypting long messages, encrypting short messages, initialization / key generation parameters