An encryption package for UNIX

Cryptography has a much wider application than secrecy, such as authentication and digital signature. There are two common types of cryptographic algoritlims - symmetric and asymmetric. The Data Encryption Standaid (DES) is the first and only, publicly available cryptographic algoritlim tliat has been widely used in commercial conmiunication. The DES is a block cipher symmetric algoritlim and its design is based on the Shannon\u27s two general principles - diffusion and confusion. With the decreased cost of hardware and a better understanding of block ciphers and cryptanalysis techniques, a number of DES-like ciphers have been proposed as the replacement for DES. One-way hashing functions are useful in implementing any digital signature schemes. A hashing function accepts a vai\u27iable size message M as input and outputs a fixed size representation of tlie message H(M). A number of hashing functions of fixed size or variable size message digest have been proposed. The cryptographic primitives (des, feal, loki, kliufu, and kliafre), block cipher based hashing algorithms (sbh and dbh), and key-less hashing algorithms (md4, md4x, md5 and haval) have been implemented as standard commands and C library calls for the UNIX Operating System

ESTABLISHED WAYS TO ATTACK EVEN THE BEST ENCRYPTION ALGORITHM

Which solution is the best – public key or private key encryption? This question cannot have a very rigorous, logical and definitive answer, so that the matter be forever settled :). The question supposes that the two methods could be compared on completely the same indicators – well, from my point of view, the comparison is not very relevant. Encryption specialists have demonstrated that the sizes of public key encrypted messages are much bigger than the encrypted message using private key algorithms. From this point of view, we can say that private key algorithms are more efficient than their newer counterparts. Looking at the issue through the eyeglass of the security level, the public key encryption have a great advantage of the private key variants, their level of protection, in the most pessimistic scenarios, being at least 35 time higher. As a general rule, each type of algorithm has managed to find its own market niche where could be applicable as a best solution and be more efficient than the other encryption model.Encryption, decryption, key, cryptanalysis, brute-force, linear, differential, algebra

The design of a secure data communication system

The recent results of using a new type of chosen-plaintext attack, which is called differential cryptanalysis, makes most published conventional secret-key block cipher systems vulnerable. The need for a new conventional cipher which resists all known attacks was the main inspiration of this work. The design of a secret-key block cipher algorithm called DCU-Cipher, that resists all known cryptanalysis methods is proposed in this dissertation. The proposed method is workable for either 64-bit plaintext/64-bit ciphertext blocks, or 128-bit plaintext/128-bit ciphertext blocks. The secret key in both styles is 128-bit long. This method has only four rounds and the main transformation function in this cipher algorithm is based on four mixed operations. The proposed method is suitable for both hardware and software implementation. It is also suitable for cryptographic hash function implementations. Two techniques for file and/or data communication encryption are also proposed here. These modes are modified versions of the Cipher-Block Chaining mode, by which the threat of the known-plaintext differential cyptanalytical attack is averted. An intensive investigation of the best known Identity-based key exchange schemes is also presented. The idea behind using such protocols, is providing an authenticated secret-key by using the users identification tockens. These kind of protocols appeared recently and are not standardized as yet. None of these protocols have been compared with previous proposals. Therefore one can not realize the efficiency and the advantages of a new proposed protocol without comparing it with other existing schemes of the same type. The aim of this investigation is to clarify the advantages and the disadvantages of each of the best known schemes and compare these schemes from the complixity and the speed viewpoint

SİMETRİK VE ASİMETRİK ŞİFRELEME ALGORİTMALARININ KARŞILAŞTIRILMASI

Şifreleme bilgisayar ağlarında haberleşme güvenliğini sağlamak için kullanılmaktadır. Bu nedenle günümüzde bilgisayarlarda ya da bilgisayar ağlarında şifrelemenin önemi gün geçtikçe artmaktadır. Bu çalışmada simetrik şifreleme algoritmaları ve asimetrik şifreleme algoritmaları hakkında bilgi verildikten sonra şifrelemede kullanılan anahtar boyutlarının analizi gerçekleştirilmiştir. Ayrıca şifreleme algoritmalarının performans kriterleri incelenmiştir

Вычисление разностных характеристик для сложения k чисел по модулю 2n

Рассматривается разностная характеристика xdp+ (а1,...,ак а0), где a0, a1, ..., ak G Zn, которая определяет вероятность преобразования разностей a1,..., ak в разность а0 (относительно побитового «исключающего или») функцией f(x1, . . . , xk) = x1 +. . . +xk mod 2n. Данная величина используется при разностном криптоанализе криптографических примитивов, содержащих «исключающее или» и сложение по модулю 2n, например ARX-конструкций. Предложены аналитические выражения для матриц, используемых для вычисления xdp+k . Кроме того, рассмотрена разностная характеристика adp® (а, в y), где а, в,3 G Zn, определяющая вероятность преобразования разностей а, в в разность y (относительно сложения по модулю 2n) функцией xфу, и получены все тройки разностей, вероятность которых больше 1/4

A simple proof of ARX completeness

In the recent years there has been a growing interest in ARX ciphers thanks to their performance in low cost architectures. This work is a short and simple proof that Add, Rotate and Exclusive-OR (ARX) operations generate the permutation group S_{2^n} and it is made up by elementary arguments with minimal use of group theory

Chaskey: a MAC Algorithm for Microcontrollers – Status Update and Proposal of Chaskey-12 –

The Chaskey MAC algorithm was presented by Mouha et al. at SAC 2014. It is designed for real-world applications where 128-bit keys are required, but standard cryptographic algorithms cannot be implemented because of stringent requirements on speed, energy consumption, or code size. Shortly after its publication, Chaskey was considered for standardization by ISO/IEC JTC 1/SC 27/WG 2. At the October 2015 meeting, the ISO/IEC committee decided to terminate the study period on Chaskey, and to circulate a first working draft. Since Chaskey was introduced, many follow-up results were published, including improved cryptanalysis results, new security proofs and more efficient implementations. This paper gives a comprehensive overview of those results, and introduces a twelve-round variant of Chaskey: Chaskey-12. Although the original eight-round Chaskey remains unbroken, Chaskey-12 has a much more conservative design, while reducing the performance by only 15% to 30%, depending on the platform