Mohamed Taoufiq Damir

University of Helsinki | HY · Department of Computer Science

We introduce a linkability attack variant on 5G AKA that we call the Replay In GUTI (RIG) attack. Our attack investigates the case where the temporary identifier GUTI is used for identification. Recalling that the GUTI-based identification is the most frequently used case, the goal of the RIG attack is to check the presence of a target user in an a...

Multi-access edge computing (MEC) is an emerging technology of 5G that brings cloud computing benefits closer to the user. The current specifications of MEC describe the connectivity of mobile users and the MEC host, but they have issues with application-level security and privacy. We consider how to provide secure and privacy-preserving communicat...

The standardized Authentication and Key Agreement protocol for 5G networks (5G AKA) have several security and privacy vulnerabilities. In this paper, we propose a novel authentication and key agreement protocol for 5G and beyond that is compatible with the standardized 5G AKA. Our protocol has several privacy and security properties, e.g., perfect...

The standardized Authentication and Key Agreement protocol for 5G networks (also known as 5G AKA) has several security and privacy vulnerabilities. For example, the 5G AKA does not undertake perfect forward secrecy. In this paper, we propose a novel quantum-safe authentication and key agreement protocol for future generation of mobile communication...

We review a lattice construction arising from quaternion algebras over number fields and use it to obtain some known extremal and densest lattices in dimensions 8 and 16. The benefit of using quaternion algebras over number fields is that the dimensionality of the construction problem is reduced by 3/4. We explicitly construct the $E_8$ lattice (re...

The design of lattice coset codes for wiretap channels is considered. Bounds on the eavesdropper’s correct decoding probability and information leakage are first revisited. From these bounds, it is explicit that both the information leakage and error probability are controlled by the average flatness factor of the eavesdropper’s lattice, which we f...

Motivated by the ring of integers of cyclic number fields of prime degree, we introduce the notion of Lagrangian lattices. Furthermore, given an arbitrary non-trivial lattice $\mathcal{L}$ we construct a family of full-rank sub-lattices $\{\mathcal{L}_{\alpha}\}$ of $\mathcal{L}$ such that whenever $\mathcal{L}$ is Lagrangian it can be easily check...

We study ideal lattices in R² coming from real quadratic fields, and give an explicit method for computing all well-rounded twists of any such ideal lattice. We apply this to ideal lattices coming from Markoff numbers to construct infinite families of non-equivalent planar lattices with good sphere-packing radius and good minimum product distance....

Ideal lattices in the plane coming from real quadratic number fields have been investigated by several authors in the recent years. In particular, it has been proved that every such ideal has a basis that can be twisted by the action of the diagonal group into a Minkowski reduced basis for a well-rounded lattice. We explicitly study such twists on...

We study ideal lattices in $\mathbb{R}^2$ coming from real quadratic fields, and give an explicit method for computing all well-rounded twists of any such ideal lattice. We apply this to ideal lattices coming from Markoff numbers to construct infinite families of non-equivalent planar lattices with good sphere-packing radius and good minimum produc...

Here, we show that if u 0 =0,u 1 =1, and u n+2 =ru n+1 +su n for all n≥0 is the Lucas sequence with s∈{±1}, then there are only finitely many effectively computable n such that ϕ(|u n |) is a power of 2, where ϕ is the Euler function. We illustrate our general result by a few specific examples. This generalizes prior results of the third author and...

Here, we study the set of positive integers n such that with F n being the nth Fibonacci number, the number F n /d+d is prime for all proper divisors d of F n .