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Hash Functions and Data Integrity
Published in Alfred J. Menezes, Paul C. van Oorschot, Scott A. Vanstone, Handbook of Applied Cryptography, 2018
Alfred J. Menezes, Paul C. van Oorschot, Scott A. Vanstone
Number 4 in a series of hash functions (Message Digest algorithms), MD4 was designed specifically for software implementation on 32-bit machines. Security concerns motivated the design of MD5 shortly thereafter, as a more conservative variation of MD4. Other important subsequent variants include the Secure Hash Algorithm (SHA-1), the hash function RIPEMD, and its strengthened variants RIPEMD-128 and RIPEMD-160. Parameters for these hash functions are summarized in Table 9.5. “Rounds × Steps per round” refers to operations performed on input blocks within the corresponding compression function. Table 9.6 specifies test vectors for a subset of these hash functions.
Blockchain Architecture, Components and Considerations
Published in Shaun Aghili, The Auditor's Guide to Blockchain Technology, 2023
Aafreen Fathima Altaf Hussain, Temitope Ipentan, Mahakpreet Singh, Grace Moyo Adeyemi
MD4 was designed by Ronald L. Rivest in 1990 [61]. It converts input messages of lengths shorter than 264 bits into a 128-bit output. It was the first cryptographic algorithm to allow efficient use of logic operations and integer calculations on 32-bit processors. Dobbertin – a cryptographer – attacked MD4 using algebraic and optimization methods that resulted in a ‘collision’. The entire message – excluding a few dozen bytes – was under the attacker’s control. After the attacks made by Den Boer and Bosselaers, Rivest immediately suggested an improved variant named MD5 [76].
Off-site construction in highways projects: management, technical, and technology perspectives from the United Kingdom
Published in Construction Management and Economics, 2023
Experience of designers, their empowerment for developing OSC solutions, and extended collaboration with the supply chain is key (Wu et al. 2019). However, the warning about introducing off-site or modular into the projects for the sake of off-site/modular or for secondary reasons, such as impressing the client and policy makers should be noted. This introduces the practice of over-prefabrication or over-modularization. Producing an available OSC systems repository with their usability matrices (MDM1) will support the design decision making and future data analytics applications for automating design optimization (TnDA1) (Gbadamosi et al. 2020). Challenging the current design mindset reliant on past data, traditional practices, and software to develop a product design mindset (MD2) and complete system thinking (MD4) is needed. This need for shifting from the construction design mode to the product design mode has been previously highlighted in the literature (Luo et al. 2017). The current gap between the designers, contractors for constructability studies, and suppliers for off-site component development and site-testing should be bridged (Goulding et al. 2015). For this, employing OSC managers to supervise the end-to-end process (MCns4) can be considered.
A secure hash function based on feedback iterative structure
Published in Enterprise Information Systems, 2019
Yijun Yang, Fei Chen, Jianyong Chen, Yong Zhang, Kai Leung Yung
On the other hand, serial hash functions should compress all message blocks one by one. The relationship among outputs of every compression functions is hereditary, which is beneficial to message diffusion effect. The most popular hash types currently in use are message digest algorithms (such as MD4, MD5) and secure hash algorithms (such as SHA1, SHA2). It is well known that MD4, MD5, SHA1 and SHA2 (including SHA224, SHA256, SHA384, SHA512) suffer from some common attacks because their similar iterative structure (Wang, Yin, and Yu 2005, Boer and Bosselaers 1994, Dobbertin date unknown, Chabaud and Joux 1998, Liang and Lai 2005, Mendel, Nad, and Schlaffer 2013, Sasaki et al. 2007, Stevens 2013, Wang et al. 2004). SHA3 (Keccak) uses sponge iterative structure which is the latest hash function announced by NIST (Bertoni, Daeman, and Peeters n.d). Although SHA3 can resist the above attacks, its vulnerability has been found by the third party cryptanalysis (Bertoni, Daeman, and Peeters n.d).
Synthesis of an Application Specific Instruction Set Processor (ASIP) for RIPEMD-160 Hash Algorithm
Published in International Journal of Electronics Letters, 2019
This step is exactly the same as the one existing in the MD4 and MD5 algorithms. The b-bit input message is extended so that its length is congruent to 448, modulo 512. In fact, a single ‘1’ bit is appended to the end of the message and then ‘0’ bits are appended so that the length in bits of the extended message becomes congruent to 448, modulo 512.