Cihangir Tezcan

E-mail

cihangir@metu.edu.tr

Department

Graduate School of Informatics

ORCID

0000-0002-9041-1932

Scopus Author ID

24447139500

Web of Science Researcher ID

D-1331-2010

Ciphertext-Only Attack on HALFLOOP-24 Dansarie, Marcus; Leander, Gregor; Rasoolzadeh, Shahram; Stennes, Lukas; Tezcan, Cihangir (2026-01-01) We present a full key-recovery ciphertext-only attack on the tweakable block cipher Halfloop-24 which is standardized by the US military and NATO for use in the Automatic Link Establishment protocol for high-frequency radi...
Fast and Energy-Efficient Polynomial Multiplication Using FFT, FFNT, and NTT on GPUs for Fully Homomorphic Encryption Özcan, Ali Şah; Tezcan, Cihangir; Savaş, Erkay (2026-01-01) Many cryptographic schemes, such as fully homomorphic encryption (FHE), zero-knowledge proofs, and post-quantum cryptography, rely on fast multiplication of large polynomials. Efficient algorithms for computing the discret...
Cryptanalysis: Theory Versus Practice Correcting Cryptanalysis Results on Ascon, ChaCha, and Serpent Using GPUs Tezcan, Cihangir; Leander, Gregor; Hadipour, Hosein (2025-09-25) Most modern cryptanalysis results are obtained through theoretical analysis, often relying on simplifications and idealized assumptions. In this work, we use the parallel computational power of GPUs to experimentally verif...
GPU Assisted Brute Force Cryptanalysis of GPRS, GSM, RFID, and TETRA Brute Force Cryptanalysis of KASUMI, SPECK, and TEA3 Tezcan, Cihangir; Leander, Gregor (2025-03-07) Key lengths in symmetric cryptography are determined with respect to the brute force attacks with current technology. While nowadays at least 128-bit keys are recommended, there are many standards and real-world applicatio...
FPGA-friendly compact and efficient AES-like 8 × 8 S-box Malal, Ahmet; Tezcan, Cihangir (2024-03-01) One of the main layers in the Advanced Encryption Standard (AES) is the substitution layer, where an 8 × 8 S-Box is used 16 times. The substitution layer provides confusion and makes the algorithm resistant to cryptanalysi...
GPU-Based Brute Force Cryptanalysis of KLEIN Tezcan, Cihangir (2024-01-01) KLEIN is a family of lightweight block ciphers that supports 64-bit, 80-bit, and 96-bit secret keys. In this work, we provide a CUDA optimized table-based implementation of the KLEIN family which does not contain shared me...
Differential-Linear Cryptanalysis of ASCON: Theory vs. Practice Tezcan, Cihangir (2023-06-22)
Experimentally Obtained Differential-Linear Distinguishers for Permutations of ASCON and DryGASCON Civek, Aslı Başak; Tezcan, Cihangir (Springer Cham, 2023-01-01) DryGASCON and Ascon are two similar authenticated encryption algorithms submitted to NIST’s recently finalized lightweight cryptography competition. DryGASCON was eliminated after the second round, while Ascon won the comp...
Cryptographic Foundations of Blockchain Technology Tezcan, Cihangir (CRC, New York , 2022-09-01)
Key lengths revisited: GPU-based brute force cryptanalysis of DES, 3DES, and PRESENT Tezcan, Cihangir (2022-03-01) Lightweight cryptographic algorithms that are tailored for resource-constrained devices sometimes use short keys which might be susceptible to brute force attacks. Such attacks using CPU or GPU might be costly because some...

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