Rusydi H. Makarim
Research Subjects
Research Interests
Rusydi H. Makarim has a total of 4 co-authors. Here are the top co-authors by number of shared publications:
- David Gerault
Technology Innovation Institute
1 shared publication - Emanuele Bellini
Technology Innovation Institute
1 shared publication - Juan Grados
Technology Innovation Institute
1 shared publication - Thomas Peyrin
Nanyang technological university, Singapore, Singapore
1 shared publication
Latest Publications
- Open Access
- 16 June 2023
- Published by Universitatsbibliothek der Ruhr-Universitat Bochum in IACR Transactions on Symmetric Cryptology
- Vol. 2023 (2) , 189-223
Boosting Differential-Linear Cryptanalysis of ChaCha7 with MILP
In this paper, we present an improved differential-linear cryptanalysis of the ChaCha stream cipher. Our main contributions are new differential-linear distinguishers that we were able to build thanks to the following improvements: a) we considered a larger search space, including 2-bit differences (besides 1-bit differences) for the difference at the beginning of the differential part of the differential-linear trail; b) a better choice of mask between the differential and linear parts; c) a carefully crafted MILP tool that finds linear trails with higher correlation for the linear part. We eventually obtain a new distinguisher for ChaCha reduced to 7 rounds that requires 2166.89 computations, improving the previous record (ASIACRYPT 2022) by a factor of 247. Also, we obtain a distinguisher for ChaCha reduced to 7.5 rounds that requires 2251.4 computations, being the first time of a distinguisher against ChaCha reduced to 7.5 rounds. Using our MILP tool, we also found a 5-round differential-linear distinguisher. When combined with the probabilistic neutral bits (PNB) framework, we obtain a key-recovery attack on ChaCha reduced to 7 rounds with a computational complexity of 2206.8, improving by a factor 214.2 upon the recent result published at EUROCRYPT 2022.
- 16 June 2023
- Published by Universitatsbibliothek der Ruhr-Universitat Bochum in IACR Transactions on Symmetric Cryptology
- Vol. 2023 (2) , 189-223
Open AccessBoosting Differential-Linear Cryptanalysis of ChaCha7 with MILP
In this paper, we present an improved differential-linear cryptanalysis of the ChaCha stream cipher. Our main contributions are new differential-linear distinguishers that we were able to build thanks to the following improvements: a) we considered a larger search space, including 2-bit differences (besides 1-bit differences) for the difference at the beginning of the differential part of the differential-linear trail; b) a better choice of mask between the differential and linear parts; c) a carefully crafted MILP tool that finds linear trails with higher correlation for the linear part. We eventually obtain a new distinguisher for ChaCha reduced to 7 rounds that requires 2166.89 computations, improving the previous record (ASIACRYPT 2022) by a factor of 247. Also, we obtain a distinguisher for ChaCha reduced to 7.5 rounds that requires 2251.4 computations, being the first time of a distinguisher against ChaCha reduced to 7.5 rounds. Using our MILP tool, we also found a 5-round differential-linear distinguisher. When combined with the probabilistic neutral bits (PNB) framework, we obtain a key-recovery attack on ChaCha reduced to 7 rounds with a computational complexity of 2206.8, improving by a factor 214.2 upon the recent result published at EUROCRYPT 2022.