Cryptographic Hash Function

This article presents a new Fast Hash-based File Existence Checking (FHFEC) method for archiving systems. During the archiving process, there are many submissions which are actually unchanged files that do not need to be re-archived. In this system, instead of comparing the entire ...

Chaotic maps are used in the design of hash functions due to their characteristics that are analogous to cryptographic requirements. However, these maps are commonly implemented using floating point representation which has high computational complexity. They also suffer from interoperability problems and are not easy to analyse from the binary point of view. These drawbacks lead to a lack of acceptance of chaos-based cryptography for practical use. This paper overcomes these problems by introducing a chaos-based hash function implemented using fixed point representation which computes digital chaotic maps using integers. Its design is based on the Merkle–Damgård construction and the generalised Feistel structure for strong security justifications. Security evaluation indicates that the proposed hash function has near-perfect statistical properties which include diffusion, confusion, collision resistance and distribution. The proposed hash function also surpasses existing chaos-based hash functions in terms of performance, making it a viable hash function for practical implementation.

The use of biometrics (e.g., fingerprints, irises, faces) for recognizing individuals is becoming increasingly popular and many applications are already available. Biometrics are intrinsically associated with individuals and cannot be forgotten or shared with others. However, one of the most relevant vulnerabilities of biometrics is that once a biometric template is compromised, it cannot be reissued, updated or destroyed. An attacker could then gain access to all the accounts/services/applications using that same biometric trait. This paper proposes a biometric verification system using distributed source coding principles, with enhanced security with respect to traditional biometric verification systems. The generation of different templates from the same biometric data is supported, as well as cancelable templates. Furthermore, it will not be possible to recover the original biometric data from the stored data, thus guaranteeing its privacy.

Cryptographic Hash Function
(in short, CHF) is a useful tool for implementing one-wayencryptionthatishardtorestoretheplaintext. CHFisdefinedasafunctionfromsome set X to fixed sized string, with almost-injective property and hard to restore theoriginal input. There are many famous algorithms such as
SHA-1
, commonly usedfor encrypting plain text into a string composed of alphabet and numbers, with size40. One interesting thing is, a
Cellular Automata
(in short, CA) has similar behavioras CHF. CA is deterministic to initial state so it’s well-defined function, and differentinitial state generates almost different output. If we take CA rule as
Life-Like Cellular Automata
(in short, LLCA), then it would be hard to guess initial state from generatedoutput since LLCA has non-deterministic property for inverse mapping, i.e., it’s
NP
problem. Therefore if we can encode given input to appropriate CA initial state andthe result, then LLCA would be suitable CHF

In this paper, we propose a new hash function based on RC4 and we call it RC4-Hash. This proposed hash function produces variable length hash output from 16 bytes to 64 bytes. Our RC4-Hash has several advantages over many popularly known hash functions. Its efficiency is comparable with widely used known hash function (e.g., SHA-1). Seen in the light of recent attacks on MD4, MD5, SHA-0, SHA-1 and on RIPEMD, there is a serious need to consider other hash function design strategies. We present a concrete hash function design with completely new internal structure. The security analysis of RC4-Hash can be made in the view of the security analysis of RC4 (which is well studied) as well as the attacks on different hash functions. Our hash function is very simple and rules out all possible generic attacks. To the best of our knowledge, the design criteria of our hash function is different from all previously known hash functions. We believe our hash function to be secure and will appreciate security analysis and any other comments.

Summary Cryptographic hash function has been used extensively in many cryptographic protocols. Many of the hash functions generate the message digest thru a randomizing process of the original message. Subsequently a chaos system also generates random behavior, but at the same time a chaos system is completely deterministic. In this paper, we propose a new hash function (CHA-1) based on chaos, which produces 160-bit hash digest, accepts message length less than 2 80 bits, and has a security factor 2 80 of brute-force attack.

This article presents a new Fast Hash-based File Existence Checking (FHFEC) method for archiving systems. During the archiving process, there are many submissions that are actually unchanged files that do not need to be re-archived. In this system, instead of comparing the entire files, only digests of the files are compared. Strong cryptographic hash functions with a low probability of collision can be used as digests.
We propose a fast algorithm to check if a certain hash, that is, a corresponding file, is already stored in the system. The algorithm is based on dividing the whole domain of hashes into equally sized regions, and on the existence of a pointer array, which has exactly one pointer for each region. Each pointer points to the location of the first stored hash from the corresponding region and has a null value if no hash from that
region exists. The entire structure can be stored in random access memory or, alternatively, on a dedicated hard disk. Statistical performance analysis has been performed that shows that in certain cases FHFEC performs nearly optimally. Extensive simulations have confirmed these analytical results. The performance
of FHFEC has been compared to the performance of a binary search (BIS) and B+tree, which are commonly used in file systems and databases for table indices. The results show that FHFEC significantly outperforms both of them.

In recent years, cryptologists have been delving into chaos theory to design more secure cryptographic primitives. However, many existing chaos-based algorithms are slow due to floating point operations. They are mostly sequential in nature and therefore cannot take advantage of multicore processors for faster speed. In this paper, a new chaos-based hash function is proposed that utilizes multiple instances of chaotic maps that run in parallel to improve hashing speed. Parallelization is realized using the baseline network that also strengthens the security of the hash function due to its shuffling mechanism. The combination of linear and nonlinear chaotic maps is used to provide a high level of sensitivity to initial conditions, confusion and diffusion characteristics as well as strong collision resistance. Results show that the proposed design has strong security strength with near-perfect statistical qualities and fast hashing speed that surpasses both chaotic hash functions and the MD5 hash function.

We have designed three fast implementations of recently proposed family of hash func- tions Edon{R. They produce message digests of length 256, 384 and 512 bits. We have deflned huge quasigroups of orders 2256, 2384 and 2512 by using only bitwise operations on 32 bit values (additions modulo 232, XORs and left rotations) and achieved processing speeds of the Reference

Cryptographic hash functions are symmetric primi-tives, used in many cryptographic protocols and as building blocks in many cryptographic functions. In general, a hash function maps a bitstring of any length, the input, to a fixed-length digest. Almost all cryptographic hash functions in ...

Nowadays, a gigantic number of constrained devices are connected to the internet. The devices interact with each other through the wireless sensor network (WSN) and provide the users with new experiences. The pervasive of devices on the internet has hugely increased which makes paramount the need for securing devices and data against threats. These devices communicate on a public channel which makes them a convenient target to be accessed by unauthorized users and break through the privacy of veritable users. Therefore, the security of constrained end nodes is important to protect data against passive or active attacks. If one single node is attacked, the network might suffer severe damage. However, many researchers find it immensely difficult to implement efficient cryptographic algorithms on constrained devices due to the limitation of their resources; the requirements on less memory and energy consumption led cryptographs to build lightweight cryptography solutions targeting confidentiality, authentication, and integrity. In this paper, we focus on authentication solutions based on lightweight hash functions. We present and compare various lightweight hash functions in terms of conception, security, and performance. According to the obtained results, we will be able to select the most appropriate lightweight hash function suitable for an authentication mechanism in IoT environments.

In this paper, we propose hPIN/hTAN, a low-cost hardware token based PIN/TAN system for protecting e-banking systems against the strong threat model where the adversary has full control over the user's computer. This threat model covers various kinds of attacks related to untrusted terminal computers, such as keyloggers, screen scrapers, session hijackers, Trojan horses and transaction generators. The core of

Cryptography and Coding theory are believed to have common roots. Foundations for both the fields were laid down by Claude Shannon. There is, however, very little research being done to investigate the relationship between the two and to see how one field can be used to benefit the other. In this contribution an interesting case study is considered to improve the channel coding results of concatenated Reed Solomon and Convolutional codes using cryptographic hash function and on the other hand to recover and verify the cryptographic hash code using the RS/Convolutional code with iterative bit flipped decoding. This is of interest for the applications that need security as well as resilience to communication errors. It is also demonstrated that a coding gain is achieved at the same time.

Cryptographic hash functions had been very significant primitives to the cryptography. They have been utilized widely in cryptographic applications and most important of them is their use in the composition of efficient Message Authentication ...

Abstract1— The use of biometrics (eg, fingerprints, irises, faces) for recognizing individuals is becoming increasingly popular and many applications are already available. Biometrics are intrinsically associated with individuals and cannot be forgotten or shared with others. ...

HMAC is a widely used message authentication code and a pseudorandom function generator based on cryptographic hash functions such as MD5 and SHA-1. It has been standardized by ANSI, IETF, ISO and NIST. HMAC is proved to be secure as long as the compression function of the underlying hash function is a pseudorandom function. In this paper we devise two new distinguishers of the structure of HMAC, called differential and rectangle distinguishers, and use them to discuss the security of HMAC based on HAVAL, MD4, MD5, SHA-0 and SHA-1. We show how to distinguish HMAC with reduced or full versions of these cryptographic hash functions from a random function or from HMAC with a random function. We also show how to use our differential distinguisher to devise a forgery attack on HMAC. Our distinguishing and forgery attacks can also be mounted on NMAC based on HAVAL, MD4, MD5, SHA-0 and SHA-1.

Signcryption is basically a cryptographic primitive which provides both signature and encryption functions simultaneously, but it is not useful when only one of the function is required. Generalized Signcryption (GSC) is a special cryptographic primitive which can provide Signcryption function when security and authencity are needed simultaneously, and can also provide encryption or signature function separately when any one of them is needed.  Generalized signcryption (GSC) scheme can adaptively work as an encryption scheme, a signature scheme or a signcryption scheme with only one algorithm. It is very suitable for storage-constrained environments. In this paper we have surveyed the existing Generalized Signcryption (GSC) schemes and compare their security properties and efficiency. Along with this we also have proposed two schemes of which first one is an Identity based Generalized Signcryption Scheme and second one is a Certificateless Generalized Signcryption scheme which is a variation of Certificateless Signcryption scheme by Barbosa et al. We begin by giving formal definition of Generalized Signcryption (GSC) primitive and complete with comparative study with other models.

Preneel, Govaerts, and Vandewalle (1993) considered the 64 most basic ways to construct a hash function from a blockcipher . They regarded 12 of these 64 schemes as secure, though no proofs or formal claims were given. Here we provide a proof-based treatment of the PGV schemes. We show that, in the ideal-cipher model, the 12 schemes considered secure by PGV really