scholarly journals On chosen target forced prefix preimage resistance

2010 ◽  
Vol 47 (1) ◽  
pp. 115-135 ◽  
Author(s):  
Michal Rjaško

Abstract In this paper we analyze the Chosen Target Forced Prefix (CTFP) preimage resistance security notion for hash functions firstly introduced in [Kelsey, J.-Kohno, T.: Herding hash functions and the Nostradamus attack, in: Advances in Cryptology-EUROCRYPT ’06, 25th Annual Internat. Conf. on the Theory and Appl. of Cryptographic Techniques (S. Vaudenay, ed.), St. Peters- burg, Russia, 2006, Lecture Notes in Comput. Sci., Vol. 4004, Springer-Verlag, Berlin, 2006, pp. 183-200]. We give a formal definition of this property in hash function family settings and work out all the implications and separations be- tween the CTFP preimage resistance and other standard notions of hash function security (preimage resistance, collision resistance, etc.). This paper follows the work of [Rogaway, P.-Shrimpton, T.: Cryptographic hash-function basics: Def- initions, implications, and separations for preimage resistance, second-preimage resistance, and collision resistance, in: Fast Software Encryption, 11th Interna- tional Workshop-FSE ’04 (B. Roy et al., eds.), Delhi, India, 2004, Lecture Notes in Comput. Sci., Vol. 3017, Springer-Verlag, Berlin, 2004, pp. 371-388], where they define seven basic notions of hash function security and examine all the relationships among these notions. We also define a new property for security of hash function families-always CTFP preimage resistance, which guarantees CTFP security for all the hash functions in the family.

Author(s):  
Stefan Kölbl ◽  
Martin M. Lauridsen ◽  
Florian Mendel ◽  
Christian Rechberger

Recently, many efficient cryptographic hash function design strategies have been explored, not least because of the SHA-3 competition. These designs are, almost exclusively, geared towards high performance on long inputs. However, various applications exist where the performance on short (fixed length) inputs matters more. Such hash functions are the bottleneck in hash-based signature schemes like SPHINCS or XMSS, which is currently under standardization. Secure functions specifically designed for such applications are scarce. We attend to this gap by proposing two short-input hash functions (or rather simply compression functions). By utilizing AES instructions on modern CPUs, our proposals are the fastest on such platforms, reaching throughputs below one cycle per hashed byte even for short inputs, while still having a very low latency of less than 60 cycles. Under the hood, this results comes with several innovations. First, we study whether the number of rounds for our hash functions can be reduced, if only second-preimage resistance (and not collision resistance) is required. The conclusion is: only a little. Second, since their inception, AES-like designs allow for supportive security arguments by means of counting and bounding the number of active S-boxes. However, this ignores powerful attack vectors using truncated differentials, including the powerful rebound attacks. We develop a general tool-based method to include arguments against attack vectors using truncated differentials.


2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Harshvardhan Tiwari ◽  
Krishna Asawa

AbstractCryptographic hash functions are important cryptographic techniques and are used widely in many cryptographic applications and protocols. All the MD4 design based hash functions such as MD5, SHA-1, RIPEMD-160 and FORK-256 are built on Merkle-Damgård iterative method. Recent differential and generic attacks against these popular hash functions have shown weaknesses of both specific hash functions and their underlying Merkle-Damgård construction. In this paper we propose a hash function follows design principle of NewFORK-256 and based on HAIFA construction. Its compression function takes three inputs and generates a single output of 256-bit length. An extra input to a compression function is a 64-bit counter (number of bits hashed so far). HAIFA construction shows strong resistance against major generic and other cryptanalytic attacks. The security of proposed hash function against generic attacks, differential attack, birthday attack and statistical attack was analyzed in detail. It is shown that the proposed hash function has high sensitivity to an input message and is secure against different cryptanalytic attacks.


2016 ◽  
Vol 26 (2) ◽  
pp. 479-493 ◽  
Author(s):  
Anna Kobusińska ◽  
Jerzy Brzeziński ◽  
Michał Boroń ◽  
Łukasz Inatlewski ◽  
Michał Jabczyński ◽  
...  

Abstract Currently existing solutions rarely protect message integrity, authenticity and user anonymity without burdening the user with details of key management. To address this problem, we present Aldeon-a protocol for anonymous group conversations in a peer-to-peer system. The efficiency of Aldeon is based on a novel tree synchronization algorithm, which is proposed and discussed in this paper. By using this algorithm, a significant reduction in the number of exchanged messages is achieved. In the paper, the formal definition of the proposed hash branch function and the proof of its efficiency are presented.


2019 ◽  
Vol 1 ◽  
pp. 125-133 ◽  
Author(s):  
Jacek Tchórzewski ◽  
Agnieszka Jakóbik

The paper presents a theoretical introduction to the cryptographic hash function theory and a statistical experimental analysis of selected hash functions. The definition of hash functions, differences between them, their strengths and weaknesses are explained as well. Different hash function types, classes and parameters are described. The features of hash functions are analyzed by performing statistical analysis. Experimental analysis is performed for three certified hash functions: SHA1-160, SHA2-512 and SHA3-512. Such an analysis helps understand the behavior of cryptographic hash functions and may be very helpful for comparing the security level of the hashing method selected. The tests may serve as a basis for examination of each newly proposed hash function. Additionally, the analysis may be harness as a method for comparing future proposals with the existing functions.


Author(s):  
Sultan Almuhammadi ◽  
Omar Mohammed Bawazeer

A cryptographic hash function is an important component used in many applications, such as blockchain, authentication, data integrity, and digital signature. With the rapid increase in usage of mobile devices, more attention goes towards the tradeoffs between performance and security of cryptographic hash functions on mobile devices due to their limited computational power. The researchers in this paper study the most common cryptographic hash functions and highlights the tradeoffs between their performance and security. The hash functions considered in this study are MD4, MD5, Whirlpool, and the hash functions in the SHA family. The security of these hash functions is compared based on recent attacks in terms of collision resistance, preimage attacks, and sensitivity analysis. While the performance is tested on different input block sizes, useful observations and recommendations are made based on the results of this study.


2019 ◽  
Vol 22 (2) ◽  
pp. 27-32
Author(s):  
Khurshida Tillahodjaeva ◽  

In this article we will talk about the scale of family and marriage relations in the early XX century in the Turkestan region, their regulation, legislation. Clearly reveals the role of women and men in the family, the definition of which is based on the material conditions of society, equality of rights and freedoms and its features.


Author(s):  
Keith M. Martin

This chapter discusses cryptographic mechanisms for providing data integrity. We begin by identifying different levels of data integrity that can be provided. We then look in detail at hash functions, explaining the different security properties that they have, as well as presenting several different applications of a hash function. We then look at hash function design and illustrate this by discussing the hash function SHA-3. Next, we discuss message authentication codes (MACs), presenting a basic model and discussing basic properties. We compare two different MAC constructions, CBC-MAC and HMAC. Finally, we consider different ways of using MACs together with encryption. We focus on authenticated encryption modes, and illustrate these by describing Galois Counter mode.


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