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

Cryptanalysis of 4-Pass HAVAL

HAVAL is a cryptographic hash function proposed by Zheng et al. Rompay et al and Wang et al found collisions of full 3-Pass HAVAL. In this paper, we study the security of 4-Pass HAVAL. We find collisions of full versions of 4-Pass HAVAL. The attack is similar to the two-block attack of MD5 proposed by Wang et al. The computational complexity of the attack is about 2^30-2^32 for the first block and 2^27-2^29 for the second block. We use this attack to find 256bit collisions of 4-Pass HAVAL in 3-4 hour on a common PC

Preimage Attacks on 3-Pass HAVAL and Step-Reduced MD5

This paper presents preimage attacks for the hash functions 3-pass HAVAL and step-reduced MD5. Introduced in 1992 and 1991 respectively, these functions underwent severe collision attacks, but no preimage attack. We describe two preimage attacks on the compression function of 3-pass HAVAL. The attacks have a complexity of about $2^{224}$ compression function evaluations instead of $2^{256}$. Furthermore, we present several preimage attacks on the MD5 compression function that invert up to 47 (out of 64) steps within $2^{96}$ trials instead of $2^{128}$. Though our attacks are not practical, they show that the security margin of 3-pass HAVAL and step-reduced MD5 with respect to preimage attacks is not as high as expected

Improved Meet-in-the-Middle Cryptanalysis of KTANTAN

We revisit meet-in-the-middle attacks on block ciphers and recent developments in meet-in-the-middle preimage attacks on hash functions. Despite the presence of a secret key in the block cipher case, we identify techniques that can also be mounted on block ciphers, thus allowing us to improve the cryptanalysis of the block cipher KTANTAN family. The first and major contribution is that we spot errors in previous cryptanalysis, secondly we improve upon the corrected results. Especially, the technique indirect-partial-matching can be used to increase the number of matched bits significantly, as exemplified by our attacks. To the best of our knowledge, this is the first time that a splice-and-cut meet-in-the-middle attack is applied to block ciphers. When the splitting point is close to the start or the end of the cipher, the attack remains to be at very low data complexity. The secret key of the full cipher can be recovered faster than exhaustive search for all three block sizes in the KTANTAN family. The attack on KTANTAN32 works with a time complexity $2^{72.9}$ in terms of full round encryptions. The attack has a time complexity of $2^{73.8}$ and $2^{74.4}$ on KTANTAN48 and KTANTAN64, respectively. Moreover, all the three attacks work with 4 chosen ciphertexts only. These results compare favourably with the factor 2 speed-up over brute force obtained in earlier work 4 , and hence these attacks are the best cryptanalysis results so far

Cryptoraptor : high throughput reconfigurable cryptographic processor for symmetric key encryption and cryptographic hash functions

textIn cryptographic processor design, the selection of functional primitives and connection structures between these primitives are extremely crucial to maximize throughput and flexibility. Hence, detailed analysis on the specifications and requirements of existing crypto-systems plays a crucial role in cryptographic processor design. This thesis provides the most comprehensive literature review that we are aware of on the widest range of existing cryptographic algorithms, their specifications, requirements, and hardware structures. In the light of this analysis, it also describes a high performance, low power, and highly flexible cryptographic processor, Cryptoraptor, that is designed to support both today's and tomorrow's encryption standards. To the best of our knowledge, the proposed cryptographic processor supports the widest range of cryptographic algorithms compared to other solutions in the literature and is the only crypto-specific processor targeting the future standards as well. Unlike previous work, we aim for maximum throughput for all known encryption standards, and to support future standards as well. Our 1GHz design achieves a peak throughput of 128Gbps for AES-128 which is competitive with ASIC designs and has 25X and 160X higher throughput per area than CPU and GPU solutions, respectively.Electrical and Computer Engineerin

DESIGN AND IMPLEMENTATION OF GEOMETRIC BASED CRYPTOGRAPHIC HASH ALGORITHM: ASH-256

Online communication takes a major part in our daily life. Since sending or receiving information over internet is inevitable, usage of hash function is essential to check whether the information is correct or not especially for sensitive or confidential information. In this paper a new cryptographic hash function, Algorithm for Secure Hashing (ASH-256) has been proposed which is based on geometric concepts. In ASH-256, each 64-bit block of a given 512-bit block is increased to 96-bits by using Expansion table (E-Table) of DES(Data Encryption Standard) algorithm and divided into two equal sub-blocks. Each sub-block is used to generate three points of a triangle, which are involved in area calculation. The calculated area values are in turn processed to generate message digest. ASH-256 is more secure and exhibits strong avalanche effect and also simple construction and easy to implemention, when compared to standard hash function SHA2(256)

D.STVL.9 - Ongoing Research Areas in Symmetric Cryptography

This report gives a brief summary of some of the research trends in symmetric cryptography at the time of writing (2008). The following aspects of symmetric cryptography are investigated in this report: • the status of work with regards to different types of symmetric algorithms, including block ciphers, stream ciphers, hash functions and MAC algorithms (Section 1); • the algebraic attacks on symmetric primitives (Section 2); • the design criteria for symmetric ciphers (Section 3); • the provable properties of symmetric primitives (Section 4); • the major industrial needs in the area of symmetric cryptography (Section 5)

An Overview of Cryptography (Updated Version, 3 March 2016)

There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting passwords. One essential aspect for secure communications is that of cryptography...While cryptography is necessary for secure communications, it is not by itself sufficient. This paper describes the first of many steps necessary for better security in any number of situations. A much shorter, edited version of this paper appears in the 1999 edition of Handbook on Local Area Networks published by Auerbach in September 1998