Cryptographic Randomness Test of the Modified Hashing Function of SHA256 to Address Length Extension Attack

Author(s):  
Dan Michael A. Cortez ◽  
Ariel M. Sison ◽  
Ruji P. Medina
1982 ◽  
Vol 17 (9) ◽  
pp. 18-27 ◽  
Author(s):  
Curtis R. Cook ◽  
R. R. Oldehoeft

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jinhua Fu ◽  
Sihai Qiao ◽  
Yongzhong Huang ◽  
Xueming Si ◽  
Bin Li ◽  
...  

Blockchain is widely used in encrypted currency, Internet of Things (IoT), supply chain finance, data sharing, and other fields. However, there are security problems in blockchains to varying degrees. As an important component of blockchain, hash function has relatively low computational efficiency. Therefore, this paper proposes a new scheme to optimize the blockchain hashing algorithm based on PRCA (Proactive Reconfigurable Computing Architecture). In order to improve the calculation performance of hashing function, the paper realizes the pipeline hashing algorithm and optimizes the efficiency of communication facilities and network data transmission by combining blockchains with mimic computers. Meanwhile, to ensure the security of data information, this paper chooses lightweight hashing algorithm to do multiple hashing and transforms the hash algorithm structure as well. The experimental results show that the scheme given in the paper not only improves the security of blockchains but also improves the efficiency of data processing.


Author(s):  
C.C. CHANG ◽  
H.C. WU

In this paper, we consider the problem of how to design a minimal perfect hashing function which is suitable for the Mandarin Phonetic Symbols system. Our main idea is inspired by Chang’s letter-oriented minimal perfect hashing scheme. By using our hashing function, 1303 Mandarin phonetic symbol transcriptions will be hashed to 1303 locations in the way of one-to-one correspondence.


Author(s):  
Rafael Álvarez-Sánchez ◽  
Alicia Andrade-Bazurto ◽  
Ivan Santos-González ◽  
Antonio Zamora-Gómez
Keyword(s):  

2020 ◽  
Vol 10 (5) ◽  
pp. 6187-6190
Author(s):  
A. S. Alshammari

The keyspace of a cryptography system must be long enough in order to protect it from brute force attacks. The One-Time Pad (OTP) encryption is unconditionally secure because of its truly random keystream that is used only once. This paper proposes a new chaotic symmetric cryptosystem approach, comparable to OTP. The proposed system utilizes two Lorenz generators, a main and an auxiliary, where the aim of the second one is to make one of the main Lorenz generator’s parameters to vary continually with time in a chaotic manner. This technique was built on digitizing two Lorenz chaotic models to increase the security level. The scrambling scheme was developed and the Lorenz stream cipher binary stream successfully passed the NIST randomness test. The cryptosystem showed a high degree of security, as it had a keyspace of 2576, and it was compared with existing symmetric key cryptography systems, such as DES, 3DES, AES, Blowfish, and OTP.


2021 ◽  
Author(s):  
Khushal Singh ◽  
Nanhay Singh

Abstract Internet of Things (IoT) is the domain of interest for the researchers at the present with the exponential growth in technology. Security in IoT is a prime factor, which highlights the need for authentication to tackle various attackers and hackers. Authentication is the process that uniquely identifies the incoming user and this paper develops an authentication protocol based on the chebyshev polynomial, hashing function, session password, and Encryption. The proposed authentication protocol is named as, proposed Elliptic, chebyshev, Session password, and Hash function (ECSH)-based multilevel authentication. For authenticating the incoming user, there are two phases, registration and authentication. In the registration phase, the user is registered with the server and Authentication center (AC), and the authentication follows, which is an eight-step criterion. The authentication is duly based on the scale factor of the user and server, session password, and verification messages. The authentication at the eight levels assures the security against various types of attacks and renders secure communication in IoT with minimal communication overhead and packet-loss. The performance of the method is analyzed using black-hole and Denial-of-service (DOS) attacks with 50 and 100 nodes in the simulation environment. The proposed ECSH-based multilevel authentication acquired the maximal detection rate, PDR, and QOS of 15.2%, 35.7895%, and 26.4623%, respectively in the presence of 50 nodes and DOS attacks, whereas the minimal delay of 135.922 ms is acquired in the presence of 100 nodes and DOS attacks.


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