scholarly journals A provably secure non-iterative hash function resisting birthday attack

2016 ◽  
Vol 654 ◽  
pp. 128-142 ◽  
Author(s):  
Shenghui Su ◽  
Tao Xie ◽  
Shuwang Lü
Keyword(s):  
Hash Function ◽  
Birthday Attack ◽  
Provably Secure

scholarly journals Provably Secure Covert Communication on Blockchain

Cryptography ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 18 ◽  
Author(s):  
Juha Partala
Keyword(s):  
Hash Function ◽  
Random Oracle Model ◽  
Data Integrity ◽  
Random Oracle ◽  
Covert Communication ◽  
Smart Contracts ◽  
Cryptographic Hash Function ◽  
Rigorous Definition ◽  
Open Nature ◽  
Provably Secure

Blockchain is a public open ledger that provides data integrity in a distributed manner. It is the underlying technology of cryptocurrencies and an increasing number of related applications, such as smart contracts. The open nature of blockchain together with strong integrity guarantees on the stored data makes it a compelling platform for covert communication. In this paper, we suggest a method of securely embedding covert messages into a blockchain. We formulate a simplified ideal blockchain model based on existing implementations and devise a protocol that enables two parties to covertly communicate through the blockchain following that model. We also formulate a rigorous definition for the security and covertness of such a protocol based on computational indistinguishability. Finally, we show that our method satisfies this definition in the random oracle model for the underlying cryptographic hash function.

scholarly journals Design of Random Oracle for Block Iterated One-Way Ciphers Through Polynomial Functions

2019 ◽  
Vol 8 (6S) ◽  
pp. 1027-1034
Keyword(s):  
Hash Function ◽  
Polynomial Function ◽  
Design Principles ◽  
Random Oracle ◽  
Higher Order ◽  
Differential Analysis ◽  
Order Polynomial ◽  
Block Level ◽  
Design Paradigm ◽  
Provably Secure

The security aspect on provably secure hash function relies upon the design principles of Random Oracle (RO). Poor design principles make the said function vulnerable to hash attacks. The conventional keyless provably secure hash functions MD-5, SHA-2 and SHA-3 use RO or Sponge principles for the design and construction of hash function. They use bitwise operators AND, OR, XOR and modulo arithmetic for processing the input blocks. These operators are simple to use and they are efficient in terms of achieving quick response time. At the same time the repeated use of them in the input blocks may invite hash collisions. The proposed design advocates the use of multi variable higher-order polynomial function for the design of round function in RO. The new design paradigm derogates the use of bitwise operators at block level processing and hardens the internal structure of RO with higher- order polynomial function to ensure better security. The results prove that, the new prototype helps the block iterated hash function to exhibit strong random behavior even for a small bit flip in the input. Therefore, performing differential analysis on the proposed design is very hard than ever before.

scholarly journals Security Analysis of Zipper Hash Against Multicollisions Attacks

2012 ◽  
Vol 2 (3) ◽  
pp. 226-231
Author(s):  
N. Bagheri
Keyword(s):  
Hash Function ◽  
Time Complexity ◽  
Security Analysis ◽  
Birthday Attack

In this paper,  the existence of multicollisions in Zipper Hash structure, a new Hash structure which was introduced to strengthen the iterated Hash structures, is presented. This study shows that finding multicollisions, i.e. 2k-way collision, in this Hash structure is not much harder than finding such  multicollisions in ordinary Merkle  - Damgard (MD)  structure. In fact, the complexity of the attacks is approximately n/2 times harder than what has been found for MD structures. Then, these large multicollisions are used as a tool to find D-way preimage for this structure. The complexity of finding 2K-way multicollisions and 2k-way preimages are  (eq) and (eq) respectively. Similar to what has been proved by Joux for MD, it is shown in this paper that this structure could not be used to create a Hash function with 2n-bit length by concatenating this structure with any other Hash structure by Hash’s output length of n-bite. It is also shown that time complexity of finding a collision for this concatenated structure is (eq)  which is much smaller than what was expected from generic-birthday attack which would be (eq) . In addition, it is shown that increasing the number of rounds of this Hash function can not improve its security against this attack significantly and the attacker can find multicollisions on this Hash function which means that this Hash function has a structural flaw.

Provably secure lightweight client authentication scheme with anonymity for TMIS using chaotic hash function

2021 ◽  
Author(s):  
Vishesh P. Gaikwad ◽  
Jitendra V. Tembhurne ◽  
Chandrashekhar Meshram ◽  
Cheng-Chi Lee
Keyword(s):  
Hash Function ◽  
Authentication Scheme ◽  
Provably Secure

Penerapan Kriptografi Keamanan Data Administrasi Kependudukan Desa Pagar Jati Menggunakan SHA-1

2020 ◽  
Vol 3 (2) ◽  
pp. 182-186
Author(s):  
Lisnayani Silalahi ◽  
Anita Sindar
Keyword(s):  
System Application ◽  
Data Security ◽  
Hash Function ◽  
Security System ◽  
Cryptographic Hash Function ◽  
Security Costs ◽  
Encryption Method

Data security and confidentiality is currently a very important issue and continues to grow. Several cases concerning data security are now a job that requires handling and security costs that are so large. To maintain the security and confidentiality of messages, data, or information so that no one can read or understand it, except for the rightful recipients, a data security system application with an encryption method using an algorithm is designed. The SHA-1 cryptographic hash function that takes input and produces a 160-bit hash value which is known as the message iteration is usually rendered as a 40-digit long hexadecimal number.

Construct Hash Function from Plaintext to C34Curves

2012 ◽  
Vol 35 (9) ◽  
pp. 1868 ◽  
Author(s):  
Wei YU ◽  
Kun-Peng WANG ◽  
Bao LI ◽  
Song TIAN
Keyword(s):  
Hash Function

Authentication protocol of mobile RFID based on Hash function

2013 ◽  
Vol 33 (5) ◽  
pp. 1350-1352
Author(s):  
Peng LIU ◽  
Changhong ZHANG ◽  
Qingyu OU
Keyword(s):  
Hash Function ◽  
Authentication Protocol ◽  
Mobile Rfid
Sign in / Sign up

Export Citation Format

Share Document