Performance factors of a CUDA GPU parallel program: A case study on a PDF password cracking brute-force algorithm

Author(s):  
Ignatius Leo Sri Hendarto ◽  
Yusuf Kurniawan
Author(s):  
Sofriesilero Zumaytis ◽  
Oscar Karnalim

Abstract—According to our informal survey, Branch & Bound strategy is considerably difficult to learn compared to other strategies. This strategy consists of several complex algorithmic steps such as Reduced Cost Matrix (RCM) calculation and Breadth First Search. Thus, to help students understanding this strategy, AP-BB, an educational tool for learning Branch & Bound is developed. This tool includes four modules which are Brute Force solving visualization, Branch & Bound solving visualization, RCM calculator, and case-based performance comparison. These modules are expected to enhance student’s understanding about Branch & Bound strategy and its characteristics. Furthermore, our work incorporates TSP as its case study and Brute Force strategy as a baseline to provide a concrete impact of Branch & Bound strategy. According to our qualitative evaluation, AP-BB and all of its features fulfil student necessities for learning Branch & Bound strategy. Keywords— Educational Tool; Branch & Bound; Algorithm Strategy; Algorithm Visualization


2021 ◽  
Vol 1 (2) ◽  
pp. 54-60
Author(s):  
Candra Irawan ◽  
Mudafiq Riyan Pratama

String matching is an algorithm for matching a text to another text or also known as a text search. There are several algorithms that can be used for string matching, including the Boyer-Moore algorithm and the Brute Force algorithm. The Boyer-Moore algorithm is a string matching algorithm published by Robert S. Boyer and J. Strother Moore in 1977. This algorithm is considered the most efficient algorithm in general applications. The Boyer-Moore algorithm starts matching characters from the pattern on the right. While the Brute Force algorithm is an algorithm that matches a pattern with all text between 0 and n-m to find the existence of a pattern in the text. These two algorithms have different patterns in the search process. In this article, a comparative analysis of the performance of the Boyer-Moore and Brute Force algorithms is carried out in a case study of the search for the Big Indonesian Dictionary (KBBI) based on Android. The search process is carried out by searching based on words and word descriptions. The results of this study indicate that the criteria for running time, the Brute Force algorithm is faster than the Boyer-Moore algorithm with the total running time of the Brute Force algorithm is 168.3 ms in words, 6994.16 ms in word descriptions, while the Boyer-Moore algorithm for running time reached 304.7 ms on the word, 8654.77 ms on the word description. In the testing criteria based on related keywords, the two algorithms can display the same list of related keywords.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Sayed Achmady

Dalam konteks kriptanalisis dan keamanan komputer, dictionary attack adalah sebuah teknik untuk melawan cipher atau melawan mekanisme otentikasi dengan cara menentukan kunci dekripsi dengan mencari kemungkinan kombinasi kata yang terdapat di dalam sebuah kamus [1]. Pada dasarnya dictionary attack adalah pengembangan dari brute force attack, yaitu mencoba memecahkan kode dengan mencoba satu per satu kemungkinan secara berulang (exhaustive search). Akan tetapi dictionary attack bukan mencoba kombinasi satu per satu karakter yang tersedia seperti brute force, melainkan mencoba kombinasi kata yang paling mungkin berhasil dengan input sebuah “list of kata” yang dapat didefinisikan (disebut juga kamus), yang biasanya berasal dari daftar kombinasi kata-kata umum yang terdapat dalam kamus, misalnya kamus bahasa Inggris. Dictionary attack merupakan serangan yang sangat efektif untuk memecahkan kode dan sering digunakan hacker untuk membobol sistem keamanan yang berupa password, seperti akun email, akun jejaring sosial, halaman administrator situs web, dan lain-lain. Dictionary attack dianggap efektif karena memanfaatkan psikologi manusia, yaitu kebiasaan bahwa pengguna akun akan menggunakan kata-kata yang lumrah dan mudah diingat sebagai password suatu akun tertentu [2]. Selain itu, dictionary attack juga dikembangkan variasinya dan semakin tinggi efektivitasnya, sehingga hingga saat ini teknik ini masih sering digunakan untuk membobol password pengguna sebuah akun. jurnal ini membahas mengenai studi dictionary attack mengenai penjelasan singkat, prinsip kerja, dan bagaimana pengembangan dari dictionary attack dalam konteks penerapannya untuk membobol password sebuah akun tertentu. Variasi dari dictionary attack yang akan dibahas dalam makalah ini yaitu dictionary attack, hybrid dictionary attack, dan pre-computed dictionary attack. Selain itu, pada makalah ini akan dianalisis kelebihan dan kelemahan dictionary attack dan masing-masing modifikasinya, serta solusi yang dapat dilakukan dalam melawan dictionary attack. Kata kunci: Dictionary Attack, password, brute force, kamus, list of hash.


2012 ◽  
Vol 532-533 ◽  
pp. 1080-1084 ◽  
Author(s):  
Zhi Cai Shi ◽  
Can Qun Yang ◽  
Qiang Wu

MD5 Crypt is a cryptographic algorithm used commonly in UNIX system for authentication. Thanks to the additional randomization of the salt and complexity of the scheme, it makes the traditional password cracking techniques invalid on common computing systems so that the security of the system is guaranteed. As a result of the thriving of petaflops heterogeneous supercomputer system in recent decades, the security of MD5 Crypt is facing a threat of brute-force attack again. However, the complexity of heterogeneous programming and the sophistication of large-scale parallelism still hamper the password recovering. In this paper, we implemented brute-force attack of MD5 Crypt on Tianhe-1A,the world’s fastest supercomputer, by organizing the assignment between CPU and GPU reasonably and making several optimizations according to MD5 Crypt for GPU. Based on the experimental results, our algorithm achieves a great scalability. It checked more than 1.8 billion passwords in a second on the full system. Thus it issues a new challenge to the security of MD5 crypt for authentication.


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