The article “Dipper: A Lightweight Hybrid SPN–ARX Block Cipher” about the block cipher created by AZTU (Azerbaijan Technical University) researchers has been published in the prestigious “Cryptography” journal.

The authors of the cipher are Yadigar Imamverdiyev, head of the AZTU Cybersecurity Department, and doctoral students of the same department, Ali Huseynli and Jalal Alizadeh.

Two approaches were combined during the design of the cipher, named Dipper – SPN (Permutation-Substitution Network) and ARX (Addition-Rotation-XOR).

Dipper is a 64-bit lightweight block cipher created for devices with limited computing resources (for example, IoT – Internet of Things), has 96 and 128-bit key options and works in 28 rounds. Each round applies, in order, a full-state key addition, sixteen parallel 4-bit GIFT S-boxes, four 16-bit word rotations, two 16-bit modular additions, and the GIFT-64 bit permutation.

The S-box and permutation are inherited from the GIFT specification and provide a compact, well-analyzed nonlinear and linear backbone; the word rotations and modular additions form the ARX layer. The key schedule employs a non-linear update with three or four S-boxes per round and a 5-bit linear-feedback shift register for round-constant generation.

Dipper has been evaluated using a unified, fully open-source methodology for both hardware, software, and cryptanalysis. Round-based Verilog implementations have been synthesized using the same flow model, along with the PRESENT, GIFT, and SIMON variants. It is especially important to note that Dipper-64/128, despite the inclusion of an additional ARX diffusion layer, is more compact than PRESENT-128 with the same key size.

The speed of the cipher in software was measured on various processor platforms, including IoT-device processors, and compared with existing ciphers in this direction.

The empirical statistical properties of the cipher were evaluated using the avalanche, strict avalanche, and bit independence criteria, and tests included in the NIST SP 800-22 statistical test suite were successfully performed on the cipher output stream. Differential cryptanalysis of the cipher was performed in detail in the MILP (mixed-integer linear programming) model, and linear, impossible differential, and integral analysis included in the standard cryptanalysis families were also successfully applied to the cipher.

This work was supported by an internal grant from the Azerbaijan Technical University for scientific research and innovation (Contract No. AzTU-DQL-M01/78447082).

It should be noted that the journal "Cryptography" is indexed in the international scientific databases Web of Science and Scopus. The journal's impact factor for 2025 is 2.4, and the 5-year impact factor is 2.3. The journal has a JCR (Journal Citation Reports) rank of Q2 (Computer Science, Theory and Methods) and a CiteScore rank of Q1 (Applied Mathematics).