Confidential algorithm for the approximate graph vertex covering problem is presented in this article. It can preserve privacy of data at every stage of the computation, which is very important in context of cloud computing. Security of our solution is based on fully homomorphic encryption scheme. The time complexity and the security aspects of considered algorithm are described.
In this article we describe the SHA-3 algorithm and its internal permutation in which potential weaknesses are hidden. The hash algorithm can be used for different purposes, such aspseudo-random bit sequences generator, key wrapping or one pass authentication, especially in weak devices (WSN, IoT, etc.). Analysis of the function showed that successful preimage attacksare possible for low round hashes, protection from which only works with increasing the number of rounds inside the function.When the hash function is used for building lightweight applications, it is necessary to apply a small number of rounds,which requires additional security measures. This article proposes a variant improved hash function protecting against preimage attacks, which occur on SHA-3. We suggest using an additional external randomness sources obtained from a lightweight PRNG or from application of the source data permutation.
Many researchers have contributed to creating Quantum Key Distribution (QKD) since the first protocol BB84 was proposed in 1984. One of the crucial problems in QKD is to guarantee its security with finite-key lengths by Privacy Amplification (PA). However, finite-key analyses show a trade-off between the security of BB84 and the secure key rates. This study analyses two examples to show concrete trade-offs. Furthermore, even though the QKD keys have been perceived to be arbitrarily secure, this study shows a fundamental limitation in the security of the keys by connecting Leftover Hash Lemma and Guessing Secrecy on the QKD keys.
In wireless mobile networks, a client can move between different locations while staying connected to the network and access the remote server over the mobile networks by using their mobile de- vices at anytime and anywhere. However, the wireless network is more prone to some security attacks, as it does not have the ingrained physical security like wired networks. Thus, the client authentication is required while accessing the remote server through wireless network. Based on elliptic curve cryptosystem (ECC) and identity-based cryptography (IBC), Debiao et al. proposed an ID-based client authentication with key agreement scheme to reduce the computation and communication loads on the mobile devices. The scheme is suitable for mobile client-server environments, is secure against different attacks and provides mutual authentication with session key agreement between a client and the remote server as they claimed. Unfotunately, this paper demonstrates that Debiao et al.’s scheme is vulnerable some cryptographic attacks, and proposed an improved ID-based client authentication with key agreement scheme using ECC. The proposed scheme is secure based on Elliptic Curve Discrete Logarithm Problem (ECDLP) and Computational Diffie-Helmann Problem (CDHP). The detail analysis shows that our scheme overcomes the drawbacks of Debiao et al.’s scheme and achieves more functionality for the client authentication with lesser computational cost than other schemes.
We address one of the weaknesses of the RSA ciphering systems i.e. the existence of the private keys that are relatively easy to compromise by the attacker. The problem can be mitigated by the Internet services providers, but it requires some computational effort. We propose the proof of concept of the GPGPU-accelerated system that can help detect and eliminate users’ weak keys. We have proposed the algorithms and developed the GPU-optimised program code that is now publicly available and substantially outperforms the tested CPU processor. The source code of the OpenSSL library was adapted for GPGPU, and the resulting code can perform both on the GPU and CPU processors. Additionally, we present the solution how to map a triangular grid into the GPU rectangular grid – the basic dilemma in many problems that concern pair-wise analysis for the set of elements. Also, the comparison of two data caching methods on GPGPU leads to the interesting general conclusions. We present the results of the experiments of the performance analysis of the selected algorithms for the various RSA key length, configurations of GPU grid, and size of the tested key set.