Improving recent side-channel attacks against the DES key schedule

Recent publications consider side-channel attacks against the key schedule of the Data Encryption Standard (DES). These publications identify a leakage model depending on the XOR of register values in the DES key schedule. Building on this leakage model, we first revisit a discrete model which assumes that the Hamming distances between subsequent round keys leak without error. We analyze this model formally and provide theoretical explanations for observations made in previous works. Next we examine a continuous model which considers more points of interest and also takes noise into account. The model gives rise to an evaluation function for key candidates and an associated notion of key ranking. We develop an algorithm for enumerating key candidates up to a desired rank which is based on the Fincke–Pohst lattice point enumeration algorithm. We derive information-theoretic bounds and estimates for the remaining entropy and compare them with our experimental results. We apply our attack to side-channel measurements of a security controller. Using our enumeration algorithm we are able to significantly improve the results reported previously for the same measurement data.

Implementasi algoritma block cipher four pada mikrokontroler STM32F103C8T6

Pada masa industri 4.0, data menjadi salah satu komponen yang wajib dilindungi. Block cipher merupakan salah satu algoritma yang digunakan untuk mengamankan data. Penelitian ini bertujuan untuk mengimplementasikan algoritma block cipher four (BCF) pada mikrokontroler. Parameter yang menjadi tolak ukur antara lain besaran flash dan RAM mikrokontroler yang terpakai, serta kecepatan eksekusi proses komputasi algoritma BCF. Mikrokontroler akan menjalankan algoritma BCF dengan urutan komputasi key-schedule, enkripsi, dan dekripsi. Setiap kali memulai proses komputasi, maka pin trigger pada mikrokontroler akan mengirimkan sinyal rising ke osiloskop dan pada saat selesai melakukan komputasi maka pin trigger mikrokontroler akan mengirimkan sinyal falling ke osiloskop. Hasil penelitian menunjukkan algoritma BCF dapat diimplementasikan pada mikrokontroler STM32F103C8T6. Flash dan RAM yang digunakan mencapai 22,02 Kb dan 5,12 Kb. Algoritma BCF yang diimplementasikan pada mikrokontroler STM32F103C8T6 mampu berjalan sampai dengan 704 kali lebih cepat jika dibandingkan dengan prosesor NIOS II, 11 kali lebih cepat dibandingkan dengan AES-Engine, dan lebih lambat 4 kali jika dibandingkan dengan BCF-Engine.

Implementasi algoritma block cipher four pada mikrokontroler STM32F103C8T6

Pada masa industri 4.0, data menjadi salah satu komponen yang wajib dilindungi. Block cipher merupakan salah satu algoritma yang digunakan untuk mengamankan data. Penelitian ini bertujuan untuk mengimplementasikan algoritma block cipher four (BCF) pada mikrokontroler. Parameter yang menjadi tolak ukur antara lain besaran flash dan RAM mikrokontroler yang terpakai, serta kecepatan eksekusi proses komputasi algoritma BCF. Mikrokontroler akan menjalankan algoritma BCF dengan urutan komputasi key-schedule, enkripsi, dan dekripsi. Setiap kali memulai proses komputasi, maka pin trigger pada mikrokontroler akan mengirimkan sinyal rising ke osiloskop dan pada saat selesai melakukan komputasi maka pin trigger mikrokontroler akan mengirimkan sinyal falling ke osiloskop. Hasil penelitian menunjukkan algoritma BCF dapat diimplementasikan pada mikrokontroler STM32F103C8T6. Flash dan RAM yang digunakan mencapai 22,02 Kb dan 5,12 Kb. Algoritma BCF yang diimplementasikan pada mikrokontroler STM32F103C8T6 mampu berjalan sampai dengan 704 kali lebih cepat jika dibandingkan dengan prosesor NIOS II, 11 kali lebih cepat dibandingkan dengan AES-Engine, dan lebih lambat 4 kali jika dibandingkan dengan BCF-Engine.

Relationships between the Chicken McNugget Problem, Mutations of Brauer Configuration Algebras and the Advanced Encryption Standard

Mutations on Brauer configurations are introduced and associated with some suitable automata to solve generalizations of the Chicken McNugget problem. Additionally, based on marked order polytopes, the new Diophantine equations called Gelfand–Tsetlin equations are also solved. The approach allows algebraic descriptions of some properties of the AES key schedule via some Brauer configuration algebras and suitable non-deterministic finite automata (NFA).

Automated Search Oriented to Key Recovery on Ciphers with Linear Key Schedule

Automatic modelling to search distinguishers with high probability covering as many rounds as possible, such as MILP, SAT/SMT, CP models, has become a very popular cryptanalysis topic today. In those models, the optimizing objective is usually the probability or the number of rounds of the distinguishers. If we want to recover the secret key for a round-reduced block cipher, there are usually two phases, i.e., finding an efficient distinguisher and performing key-recovery attack by extending several rounds before and after the distinguisher. The total number of attacked rounds is not only related to the chosen distinguisher, but also to the extended rounds before and after the distinguisher. In this paper, we try to combine the two phases in a uniform automatic model.Concretely, we apply this idea to automate the related-key rectangle attacks on SKINNY and ForkSkinny. We propose some new distinguishers with advantage to perform key-recovery attacks. Our key-recovery attacks on a few versions of round-reduced SKINNY and ForkSkinny cover 1 to 2 more rounds than the best previous attacks.