Anas Melhem

An Assistant Professor in the Computer System Engineering department at Palestine Technical University. He earned his PhD in Computer Engineering from Eastern Mediterranean University, North Cyprus, under the supervision of Prof. Dr. Alexander Chefranov.

A major accomplishment of his doctoral research was the development of RCPKC, an advanced public key cryptosystem that is an integer-based NTRU variant resilient to lattice-based attacks. This innovative system was created through close collaboration with fellow researchers.

His main research interests are in designing and analyzing cryptographic algorithms, their applications, and the formulation and proof of their security properties. His work includes lattice-based cryptography and cryptographic primitives with extra functionality, such as homomorphic encryption.

Additionally, he has conducted extensive analysis and cryptanalysis of various symmetric and asymmetric cryptosystems, including developing a ciphertext-only attack on RSA using lattice basis reduction. His research aims to enhance the robustness of these systems against potential vulnerabilities, ensuring their reliability and security in real-world applications.

news

May 15, 2024	“TAO at StanceEval2024 Shared Task: Arabic Stance Detection using AraBERT” is accepted to appear at ACL 2024 (CORE Rank: A*)!

selected publications

IAJIT

Ciphertext-only attack on RSA using lattice basis reduction

Anas Ibrahim, Alexander G. Chefranov, and Rushdi Hamamreh

Int. Arab J. Inf. Technol., 2021

Bib HTML PDF

@article{IbrahimCH21,
  author = {Ibrahim, Anas and Chefranov, Alexander G. and Hamamreh, Rushdi},
  title = {Ciphertext-only attack on {RSA} using lattice basis reduction},
  journal = {Int. Arab J. Inf. Technol.},
  volume = {18},
  number = {2},
  pages = {237--247},
  year = {2021},
  url = {https://doi.org/10.34028/iajit/18/2/13},
  doi = {10.34028/IAJIT/18/2/13},
  timestamp = {Mon, 28 Aug 2023 21:35:42 +0200},
  biburl = {https://dblp.org/rec/journals/iajit/IbrahimCH21.bib},
  bibsource = {dblp computer science bibliography, https://dblp.org},
}

Sensors
NTRU-Like Random Congruential Public-Key Cryptosystem for Wireless Sensor Networks

Anas Ibrahim, Alexander Chefranov, Nagham Hamad, Yousef-Awwad Daraghmi, Ahmad Al-Khasawneh, and Joel J. P. C. Rodrigues

Sensors, 2020

Abs Bib HTML PDF Supp Code

Wireless sensor networks (WSNs) are the core of the Internet of Things and require cryptographic protection. Cryptographic methods for WSN should be fast and consume low power as these networks rely on battery-powered devices and microcontrollers. NTRU, the fastest and secure public key cryptosystem, uses high degree, N, polynomials and is susceptible to the lattice basis reduction attack (LBRA). Congruential public key cryptosystem (CPKC), proposed by the NTRU authors, works on integers modulo q and is easily attackable by LBRA since it uses small numbers for the sake of the correct decryption. Herein, RCPKC, a random congruential public key cryptosystem working on degree N=0 polynomials modulo q, is proposed, such that the norm of a two-dimensional vector formed by its private key is greater than q. RCPKC works as NTRU, and it is a secure version of insecure CPKC. RCPKC specifies a range from which the random numbers shall be selected, and it provides correct decryption for valid users and incorrect decryption for an attacker using LBRA by Gaussian lattice reduction. RCPKC asymmetric encryption padding (RAEP), similar to its NTRU analog, NAEP, is IND-CCA2 secure. Due to the use of big numbers instead of high degree polynomials, RCPKC is about 27 times faster in encryption and decryption than NTRU. Furthermore, RCPKC is more than three times faster than the most effective known NTRU variant, BQTRU. Compared to NTRU, RCPKC reduces energy consumption at least thirty times, which allows increasing the life-time of unattended WSNs more than thirty times.
@article{s20164632, author = {Ibrahim, Anas and Chefranov, Alexander and Hamad, Nagham and Daraghmi, Yousef-Awwad and Al-Khasawneh, Ahmad and Rodrigues, Joel J. P. C.}, title = {NTRU-Like Random Congruential Public-Key Cryptosystem for Wireless Sensor Networks}, journal = {Sensors}, volume = {20}, year = {2020}, number = {16}, article-number = {4632}, url = {https://www.mdpi.com/1424-8220/20/16/4632}, pubmedid = {32824585}, issn = {1424-8220}, doi = {10.3390/s20164632}, }