scholarly journals Formal Proofs of Cryptographic Security of Diffie-Hellman-Based Protocols

2008 ◽  
pp. 312-329 ◽  
Author(s):  
Arnab Roy ◽  
Anupam Datta ◽  
John C. Mitchell
Keyword(s):  
Formal Proofs ◽  
Diffie Hellman ◽  
Cryptographic Security

Implementasi Keamanan pada Transaksi Data Menggunakan Sertifikat Digital X.509

2017 ◽  
Vol 8 (1) ◽  
pp. 1-10
Author(s):  
Is Mardianto ◽  
Kuswandi Kuswandi
Keyword(s):  
Mobile Phone ◽  
Web Service ◽  
Data Exchange ◽  
User Authentication ◽  
Digital Certificate ◽  
Security Issues ◽  
Diffie Hellman ◽  
Digital Certificates ◽  
Mobile Phone Applications ◽  
Secure Hash Algorithm

Security issues have become a major issue on the Internet. One of the security methods that are widely used today is to implement a digital certificate. Digital certificates have evolved over time, one of which is the X.509 digital certificate. Digital certificates have been widely used as authentication applications, web network authentication and other authentication systems that require digital certificates. This research is carried out by implementing an X.509 digital certificate technology as a mobile web service with its client. Secure Hash Algorithm (SHA), Diffie-Hellman, and Advanced Encryption Standard (AES) are used to secure the data exchange transaction between the web service and mobile phone. SHA algorithm will be used for user authentication, Diffie-Hellman algorithm will be used for public key exchange and AES algorithms will be used for symmetric cryptography data. The results of the application of digital certificates, the SHA algorithm, Diffie-Hellman, and AES in mobile phone applications, provide security application running on web service. Index Terms—Digital Certificate, X.509, SHA, Diffie Hellman, AES

scholarly journals Optimized CSIDH Implementation Using a 2-Torsion Point

Cryptography ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 20 ◽  
Author(s):  
Donghoe Heo ◽  
Suhri Kim ◽  
Kisoon Yoon ◽  
Young-Ho Park ◽  
Seokhie Hong
Keyword(s):  
Elliptic Curve ◽  
Group Action ◽  
Large Degree ◽  
Transitive Group ◽  
Optimization Method ◽  
Torsion Point ◽  
Torsion Points ◽  
Diffie Hellman ◽  
Odd Degree ◽  
Montgomery Curve

The implementation of isogeny-based cryptography mainly use Montgomery curves, as they offer fast elliptic curve arithmetic and isogeny computation. However, although Montgomery curves have efficient 3- and 4-isogeny formula, it becomes inefficient when recovering the coefficient of the image curve for large degree isogenies. Because the Commutative Supersingular Isogeny Diffie-Hellman (CSIDH) requires odd-degree isogenies up to at least 587, this inefficiency is the main bottleneck of using a Montgomery curve for CSIDH. In this paper, we present a new optimization method for faster CSIDH protocols entirely on Montgomery curves. To this end, we present a new parameter for CSIDH, in which the three rational two-torsion points exist. By using the proposed parameters, the CSIDH moves around the surface. The curve coefficient of the image curve can be recovered by a two-torsion point. We also proved that the CSIDH while using the proposed parameter guarantees a free and transitive group action. Additionally, we present the implementation result using our method. We demonstrated that our method is 6.4% faster than the original CSIDH. Our works show that quite higher performance of CSIDH is achieved while only using Montgomery curves.

Reduction of the integer factorization complexity upper bound to the complexity of the Diffie–Hellman problem

2021 ◽  
Vol 31 (1) ◽  
pp. 1-4
Author(s):  
Mikhail A. Cherepnev
Keyword(s):  
Upper Bound ◽  
Polynomial Algorithm ◽  
Integer Factorization ◽  
Factorization Problem ◽  
Diffie Hellman ◽  
Integer Factorization Problem

Abstract We construct a probabilistic polynomial algorithm that solves the integer factorization problem using an oracle solving the Diffie–Hellman problem.

Research on psychological stress intervention of college students based on Diffie-hellman key exchange algorithm

2021 ◽  
pp. 1-7
Author(s):  
Yibo Liu ◽  
Xuejing Hao ◽  
Yanjun Mao
Keyword(s):  
College Students ◽  
Psychological Stress ◽  
Original Data ◽  
Key Exchange ◽  
Psychological Burden ◽  
Exchange Algorithm ◽  
Diffie Hellman ◽  
Stress Intervention ◽  
Psychological Pressure ◽  
Diffie Hellman Key Exchange

At present, the mental health of college students has also become an important issue that urgently needs attention under the influence of the surrounding environment. It is coupled with the grim employment situation after graduation and the students’ psychological burden is becoming more and heavier. This paper based on Diffie-Hellman key exchange algorithm studied the effect of psychological stress intervention. First, the Diffie-Hellman key exchange algorithm was analyzed, and then the Diffie-Hellman prediction model was established according to the psychological pressure of college students. Secondly, the simulation test was conducted to compare the simulated results with the original data. The conclusion of the data fitting of the network model training set, verification set and test set were good and the error was very small. Finally, the detailed application of the algorithm and the model were described.

scholarly journals Timing attacks and local timing attacks against Barrett’s modular multiplication algorithm

2021 ◽  
Author(s):  
Johannes Mittmann ◽  
Werner Schindler
Keyword(s):  
Side Channel ◽  
Modular Exponentiation ◽  
Modular Multiplication ◽  
Multiplication Algorithm ◽  
Diffie Hellman ◽  
Mathematical Difficulties ◽  
Execution Times ◽  
Stochastic Properties ◽  
Timing Attacks ◽  
Theoretical Results

AbstractMontgomery’s and Barrett’s modular multiplication algorithms are widely used in modular exponentiation algorithms, e.g. to compute RSA or ECC operations. While Montgomery’s multiplication algorithm has been studied extensively in the literature and many side-channel attacks have been detected, to our best knowledge no thorough analysis exists for Barrett’s multiplication algorithm. This article closes this gap. For both Montgomery’s and Barrett’s multiplication algorithm, differences of the execution times are caused by conditional integer subtractions, so-called extra reductions. Barrett’s multiplication algorithm allows even two extra reductions, and this feature increases the mathematical difficulties significantly. We formulate and analyse a two-dimensional Markov process, from which we deduce relevant stochastic properties of Barrett’s multiplication algorithm within modular exponentiation algorithms. This allows to transfer the timing attacks and local timing attacks (where a second side-channel attack exhibits the execution times of the particular modular squarings and multiplications) on Montgomery’s multiplication algorithm to attacks on Barrett’s algorithm. However, there are also differences. Barrett’s multiplication algorithm requires additional attack substeps, and the attack efficiency is much more sensitive to variations of the parameters. We treat timing attacks on RSA with CRT, on RSA without CRT, and on Diffie–Hellman, as well as local timing attacks against these algorithms in the presence of basis blinding. Experiments confirm our theoretical results.

scholarly journals Extremal Values of the Sackin Tree Balance Index

2021 ◽  
Author(s):  
Mareike Fischer
Keyword(s):  
Phylogenetic Trees ◽  
Theoretical Computer Science ◽  
Search Trees ◽  
Formal Proofs ◽  
Birth Process ◽  
Ordered Trees ◽  
Research Areas ◽  
New Findings ◽  
Mathematical Phylogenetics ◽  
Extremal Values

AbstractTree balance plays an important role in different research areas like theoretical computer science and mathematical phylogenetics. For example, it has long been known that under the Yule model, a pure birth process, imbalanced trees are more likely than balanced ones. Also, concerning ordered search trees, more balanced ones allow for more efficient data structuring than imbalanced ones. Therefore, different methods to measure the balance of trees were introduced. The Sackin index is one of the most frequently used measures for this purpose. In many contexts, statements about the minimal and maximal values of this index have been discussed, but formal proofs have only been provided for some of them, and only in the context of ordered binary (search) trees, not for general rooted trees. Moreover, while the number of trees with maximal Sackin index as well as the number of trees with minimal Sackin index when the number of leaves is a power of 2 are relatively easy to understand, the number of trees with minimal Sackin index for all other numbers of leaves has been completely unknown. In this manuscript, we extend the findings on trees with minimal and maximal Sackin indices from the literature on ordered trees and subsequently use our results to provide formulas to explicitly calculate the numbers of such trees. We also extend previous studies by analyzing the case when the underlying trees need not be binary. Finally, we use our results to contribute both to the phylogenetic as well as the computer scientific literature using the new findings on Sackin minimal and maximal trees to derive formulas to calculate the number of both minimal and maximal phylogenetic trees as well as minimal and maximal ordered trees both in the binary and non-binary settings. All our results have been implemented in the Mathematica package SackinMinimizer, which has been made publicly available.

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