ricik

Ricik is a lightweight, open‑source cryptographic library that implements the Ricik cipher, a symmetric‑key algorithm described in the 2019 paper “Ricik: A Substitution‑Permutation Network for Secure Embedded Systems.” The library was authored by a team of researchers at the University of Tartu, led by Dr. A. R. K. Vec, whose initials inspired the name. Ricik’s design focuses on low memory consumption and rapid execution, making it suitable for resource‑constrained environments such as smart cards, IoT devices, and embedded controllers.

The Ricik cipher itself follows a 64‑bit block size and 128‑bit key length. Its architecture consists of eight rounds of substitution layers, each driven by a small S‑box table, and a linear diffusion layer based on matrix multiplication over GF(2). Security analysis presented in the original publication shows resistance against linear and differential cryptanalysis up to the available computational limits, with no discovered structural weaknesses up to full 12‑round encryption. Subsequent independent analyses have confirmed the cipher’s resilience against known attacks while highlighting areas for future work such as side‑channel resistance and hardware optimization.

The Ricik library is released under a permissive BSD‑3 style license, encouraging community contributions. It offers bindings for C, C++, and Python, and includes a minimal command‑line utility for encrypting and decrypting small files. While the library has not yet seen widespread adoption in commercial products, it has been cited in several academic works discussing lightweight cryptography for embedded systems. The project maintains an active issue tracker and regularly implements community‑suggested improvements, ranging from algorithmic tunings to platform‑specific assembly optimizations.

Overall, Ricik represents a modest yet well‑designed approach to providing secure, high‑performance encryption in constrained devices, and serves as a useful reference point for researchers and engineers working on embedded cryptographic solutions.