scholarly journals Authenticated Diffie-Hellman Key Agreement Scheme that Protects Client Anonymity and Achieves Half-Forward Secrecy

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Hung-Yu Chien

Authenticated Diffie-Hellman key agreement (D-H key) is the de facto building block for establishing secure session keys in many security systems. Regarding the computations of authenticated D-H key agreement, the operation of modular exponentiation is the most expensive computation, which incurs a heavy loading on those clients where either their computational capacities or their batteries are limited and precious. As client’s privacy is a big concern in several e-commerce applications, it is desirable to extend authenticated D-H key agreement to protect client’s identity privacy. This paper proposes a new problem: the modified elliptic curves computational Diffie-Hellman problem (MECDHP) and proves that the MECDHP is as hard as the conventional elliptic curves computational Diffie-Hellman problem (ECDHP). Based on the MECDHP, we propose an authenticated D-H key agreement scheme which greatly improves client computational efficiency and protects client’s anonymity from outsiders. This new scheme is attractive to those applications where the clients need identity protection and lightweight computation.

Author(s):  
Anna ILYENKO ◽  
Sergii ILYENKO ◽  
Yana MASUR

In this article, the main problems underlying the current asymmetric crypto algorithms for the formation and verification of electronic-digital signature are considered: problems of factorization of large integers and problems of discrete logarithm. It is noted that for the second problem, it is possible to use algebraic groups of points other than finite fields. The group of points of the elliptical curve, which satisfies all set requirements, looked attractive on this side. Aspects of the application of elliptic curves in cryptography and the possibilities offered by these algebraic groups in terms of computational efficiency and crypto-stability of algorithms were also considered. Information systems using elliptic curves, the keys have a shorter length than the algorithms above the finite fields. Theoretical directions of improvement of procedure of formation and verification of electronic-digital signature with the possibility of ensuring the integrity and confidentiality of information were considered. The proposed method is based on the Schnorr signature algorithm, which allows data to be recovered directly from the signature itself, similarly to RSA-like signature systems, and the amount of recoverable information is variable depending on the information message. As a result, the length of the signature itself, which is equal to the sum of the length of the end field over which the elliptic curve is determined, and the artificial excess redundancy provided to the hidden message was achieved.


Author(s):  
Johannes Mittmann ◽  
Werner Schindler

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.


Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 188
Author(s):  
Shadi Nashwan

Smart irrigation is considered one of the most significant agriculture management systems worldwide, considering the current context of water scarcity. There is a clear consensus that such smart systems will play an essential role in achieving the economic growth of other vital sectors. In general, the consequences of global warming and the unavailability of clean water sources for the agricultural sector are clear indications that the demand for these systems will increase in the near future, especially considering the recent expansions in the use of the Internet of Things (IoT) and Wireless Sensor Network (WSN) technologies, which have been employed in the development of such systems. An obvious result is that security challenges will be one of the main obstacles to attaining the widespread adoption of such systems. Therefore, this paper proposes a secure authentication scheme using Diffie–Hellman key agreement for smart IoT irrigation systems using WSNs. This scheme is based on Diffie–Hellman and one-way hash cryptographic functions in order to support the basic security services with a high data rate and ability to resist well-known attacks. The Burrows–Abadi–Needham (BAN) logic model is used to verify the proposed scheme formally. Based on various possible attack scenarios, a resistance analysis of the proposed scheme is discussed. Further analyses are performed in terms of the storage size, intercommunication, and running time costs. Therefore, the proposed scheme not only can be considered a secure authentication scheme but is also practical for smart IoT irrigation systems due to its reasonable efficiency factors.


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