Weakness of Zhang-Wang Scheme Without Using One-Way Hash Function

Digital signature schemes based on public-key cryptosystems are important building blocks of key agreement protocols. They are vulnerable by existential forgery attack. A usual method to prevent existential forgery attack is on-way hash function and message redundancy. In 2004, Chang and Chang proposed a new digital signature scheme. The scheme is without using one-way hash function and any redundancy padding, which is very interesting to many designers. Recently, Chien found an existential forgery attack. In this paper, we show another forgery attack on it and propose an improved scheme without oracle, which is secure against existential forgery attacks. Then we proposed a key agreement protocol by amending the signature slightly.

Security of robust generalized MQV key agreement protocol without using one-way hash functions

One-way hash functions are an important tool in achieving authentication and data integrity. The aim of this paper is to propose a novel one-way hash function based on cellular automata whose cryptographic properties have been extensively studied over the past decade or so. Furthermore, security of the proposed one-way hash function is analyzed by the use of very recently published results on applications of cellular automata in cryptography. The analysis indicates that the one-way hash function is secure against all known attacks. An important feature of the proposed one-way hash function is that it is especially suitable for compact and fast implementation in hardware, which is particularly attractive to emerging security applications that employ smart cards, such as digital identification cards and electronic cash payment protocols,

Recently, Chang et al., (2004) proposed a new digital signature scheme with message recovery and claimed that neither one-way hash functions nor message redundancy schemes were employed in their scheme. However, in this letter, two forgery attacks are proposed to show that Chang et al.'s signature scheme is not secure. To resist these attacks, the message redundancy schemes may still be used.

Recently, formal complexity-theoretic treatment of cryptographic hash functions was suggested. Two primitives of Collision-free hash functions and Universal one-way hash function families have been defined. The primitives have numerous applications in secure information compression, since their security implies that finding collisions is computationally hard. Most notably, Naor and Yung have shown that the most secure signature scheme can be reduced to the existence of universal one-way hash (this, in turn, gives the first trapdoor-less provably secure signature scheme).In this work, we first present reductions from various one-way function families to universal one-way hash functions. Our reductions are general and quite efficient and show how to base universal one-way hash functions on any of the known concrete candidates for one-way functions. We then show equivalences among various definitions of hardness for collision-free hash functions.

Passwords are barriers that protect unauthorized users from accessing personal information in any application. Protecting passwords is one of the challenging tasks in today's world. Currently, a combination of Username/Password used for authentication for a large number of applications. Malicious users might try to steal/misuse the user's data for unethical purposes. To prevent passwords from stealing, developers prefer to use one-way hash functions. One-way hash functions are theoretically irreversible functions that take as an input variable size text and output fixed-sized text. In reality, hash functions are not collision-resistant. Therefore it is recommended to use passwords and randomly generated text called salt to generate hash values and prevent rainbow tables and dictionary attacks. Passwords are hashed at the client-side and sent across the public channel/network. A salt is a randomly generated alphanumeric text used to concatenate with a password to generate a random hash value. This paper demonstrates how the random generation of salt is dependent on passwords and how hash values are dependent on salt. Further, analysis of the behaviour of passwords and hash values using various tools like Wireshark, Ettercap, and Hydra are presented in the paper.

Naor and Yung (1989) show that a one-bit-compressing universal one-way hash function (UOWHF) can be constructed based on a one-way permutation. This construction can be iterated to build a UOWHF which compresses by /spl epsiv/n bits, at the cost of /spl epsiv/n invocations of the one-way permutation. The show that this construction is not far from optimal, in the following sense, there exists an oracle relative to which there exists a one-way permutation with inversion probability 2/sup -p(n)/ (for any p(n)/spl isin//spl omega/(log n)), but any construction of an /spl epsiv/n-bit-compressing UOWHF. Requires /spl Omega/(/spl radic/n/p(n)) invocations of the one-way permutation, on average. (For example, there exists in this relativized world a one-way permutation with inversion probability n/sup -/spl omega/(1)/, but no UOWHF that involves it fewer than /spl Omega/(/spl radic/n/log n) times.) Thus any proof that a more efficient UOWHF can be derived from a one-way permutation is necessarily non-relativizing; in particular, no provable construction of a more efficient UOWHF can exist based solely on a black box one-way permutation. This result can be viewed as a partial justification for the practice of building efficient UOWHFs from stronger primitives (such as collision intractable hash functions), rather than from weaker primitives such as one-way permutations.

The authors introduce encryption-free message authentication based entirely on the use of one-way hash functions. It is shown that fast one-way hash functions such as MD4 can be used as a foundation for some relatively novel implementations of security services. In particular, simple and inexpensive secret prefix and secret suffix methods provide protection against message substitution attacks when used in conjunction with a strong one-way hash function (which itself protects against message modification).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

This paper presents a new group key management protocol, CKC (Code for Key Calculation). This protocol is based on logical key hierarchy. When a new member joins the group, server sends only the group key for that member. Then, current members and the new member calculate the necessary keys using node codes and one-way hash function. Node code is a code which is assigned to each node of the key tree. Again at leave, server just sends the new group key to remaining members. By this key, members calculate necessary keys using node codes and one-way hash function. The security of the keys is based on one-wayness of hash function. The results show that CKC reduces computational and communication overhead and message size at join while it keeps minimized the overhead of key update at leave.

Fast message integrity and authentication services are much desired in today's high-speed network protocols. Current message authentication techniques are mostly encryption-based which is undesirable for several reasons. In this brief paper, we introduce encryption-free message authentication based entirely on fast one-way hash functions. Two methods are presented and their strength is analyzed. The security of the proposed methods is based on the strength of the underlying one-way hash function.

A blockchain is a distributed database; its integrity is ensured by Cryptographic Hash functions; it can be public or private. Cryptographic Hash Functions are one-way functions that transform various inputs into a fixed length output. They are used for checking the integrity of files, protecting passwords, and for proof of work. A blockchain is stored on many nodes; once the data reaches a determined size, it is hashed, and its hash forms the first line of the next block. The advantages of the blockchains are they are immutable, data is not corrupted by the host computer, and they can provide good anonymity. The disadvantages are they consume many times more energy for storing the same quantity of data, and they are vulnerable to 51% Attacks. Blockchains can enhance cybersecurity to very high levels. They are and can be used in cryptocurrencies, smart contracts, transferring financial instruments, Distributed DNS, Public Key Infrastructure, Certifying Authorities, anonymizing data in health care industry, as repositories of public registers, IoT, traceability and supply chain management, public register of antiquities, etc. Blockchain is a paradigm shift in the way data is guarded and shared.

Recently, a fast and secure hash function SFHA - 256 has been proposed and claimed as more secure and as having a better performance than the SHA - 256. In this paper an improved version of SFHA - 256 is proposed and analyzed using two parameters, namely the avalanche effect and uniform deviation. The experimental results and further analysis ensures the performance of the newly proposed and improved SFHA-256. From the analysis it can be concluded that the newly proposed algorithm is more secure, efficient, and practical.

This paper presents a novel keyed one-way Hash function based on a chaotic dynamic S-Box together with traditional one-way Hash function construction. The proposed approach can give a chaotic Hash value by means of the look up table of functions and chaotic dynamic S-Box. Compared with the existing chaotic Hash functions, this method improves computational performance of Hash system by using the chaotic dynamical S-Box substitution in place of iterating the original message directly in chaos system. Theoretical and experimental results show that the proposed method has strong one way property, large key space, sensitivity to initial conditions and chaotic system's parameters.

Remote user authentication is a mechanism in which the remote server verifies the legitimacy of a user over an insecure communication channel. Password based authentication schemes have been widely deployed to verify the legitimacy of remote users as password authentication is one of the simplest and the most convenient authentication mechanism over insecure networks. In remote user authentication scheme, the user is assigned a smart card, which is being personalized by some parameters and provide the legal users to use the resources of the remote system. Until now, there have been ample of remote user authentication schemes published in the literature and each published schemes have its own merits and demerits. Recently, many schemes proposed are based on the one-way hash function. The computational complexity of their schemes is superior to the discrete logarithm-problem-based schemes. In our paper, we have defined all the security requirements and the goals. An ideal password authentication schemes should satisfy and achieve all of these. We have presented the results of our survey through five of the currently available secure one way hash function based remote user authentication schemes. We hope an ideal smart card (not storing (ID i ,PW i ), which meets all the security requirements and achieves all the goals can be developed.

Hash functions are one-way functions that map arbitrary-length input to fixed-length output. Moreover, they have many cryptographic applications, such as integrity checks, password storage, and signatures. Cryptographic hash functions have some additional properties that can be formulated as hard problems: pre-image resistance, second pre-image resistance, and collision resistance. A significant technological development in this area is unlikely. Standardized hash functions are considered secure, and open-source implementations can be used at no cost. To conclude, the security properties required from hash functions depend on the intended purpose.