# SIMECK-T: An Ultra-Lightweight Encryption Scheme for Resource-Constrained Devices
## 2 Methodology
### Implementation
The NIST statistical tests [24] and the AIS.31 [25,26] standards have been used to validate the randomness of the output produced by SIMECK-T. Most importantly, SIMECK-T has been shown not only to be very fast but also to successfully pass the law of the iterated logarithm (LIL) proposed by [PERSON] as a stronger requirement for pseudorandom generators [28,89]. Several evaluation metrics have been used to show that the encryption scheme is secure compared to other solutions. The \(\chi^{2}\) test proposed by [PERSON] [73] shows that SIMECK-T produces random output. Linear and differential cryptanalysis have been attempted in the proposed encryption scheme using custom tools made available as free software [34]. A number of \(2^{32}\) pairs of random plaintext and corresponding ciphertext blocks were sampled without finding any linear patterns. For differential cryptanalysis, a pool of \(10^{7}\) differential pairs was sampled without detecting any relationship. Characteristic Automated Search of Cryptographic Algorithms for Distinguishing Attacks (CASCADA) is a Python-based software library that can be used for the automatic analysis of ARX ciphers [103] or encryption schemes such as SIMECK-T. It is based on modulo theories of satisfiability (SMT) and SMT solvers, and it requires that encryption primitives are ported within the framework [104]. The proposed encryption scheme was implemented in block counter mode (CTR), which is parallelizable but does not provide authentication. Galois/Counter Mode (GCM) can be implemented in order to achieve both parallelization and authentication, although devices with very limited resources may be better suited for the actual mode of operation. White-box cryptography aims to implement algorithms in software so that secret keys remain secure, even when faced with white-box attempts to extract them from the software itself [105]. A white-box implementation of SIMECK-T should add an additional layer of security [106], most importantly one-wayness [107], preventing decryption when the algorithm runs in hostile environments. Conceptualization, A.-A.A.; methodology, A.-A.A.; software, A.-A.A., P.C. and R.-D.C.; validation, A.-A.A., P.C. and R.-D.C.; investigation, A.-A.A., P.C. and E.-A.C.; resources, A.-A.A., P.C. and E.-A.C.; data curation, P.C. and E.-A.C.; writing--original draft preparation, A.-A.A. and E.-A.C.; writing--review and editing, P.C. and E.-A.C.; visualization, A.-A.A.; supervision,A.-A.A.; project administration, A.-A.A.; funding acquisition, A.-A.A. All authors have read and agreed to the published version of the manuscript. This paper benefited from financial support through the Program on \"Supporting the research activity by funding an internal grant competition--SACER 2023\", Politehnica University Timisoara, Competition 2022. The data associated with this article are fully reproducible. The true hardware number generator data and the analysis provided by statistical tests for encrypted files are available at [[https://staff.cs.upt.ro/~alin_anton/BANPUMP/datasets/SIMECK-T](https://staff.cs.upt.ro/~alin_anton/BANPUMP/datasets/SIMECK-T)]([https://staff.cs.upt.ro/~alin_anton/BANPUMP/datasets/SIMECK-T](https://staff.cs.upt.ro/~alin_anton/BANPUMP/datasets/SIMECK-T)) accessed on (11 November 2024). Data are available under the terms of the Creative Commons Zero \"No rights reserved\" data waiver (CCO 1.0 Public domain dedication). The authors declare no conflicts of interest. Sponsors had no role in the design of the study; in the collection, analysis, or interpretation of the data; in the writing of the manuscript; or in the decision to publish the results.