A homogeneous parallel brute force cracking algorithm on the GPU

From the early days of computing, passwords have been considered as the essential authentication method to protect accesses to computer systems and users. Due to their importance, sensitiveness and confidentiality, many cryptography mechanisms have been utilized to secure password storage. Among them, cryptography hash methods are the most popular solutions. A cryptography hash function converts plaintext passwords to unreadable message digests which frustrates attackers from exploiting system failures and stealing stored passwords. On the other hand, it is possible to get the plaintext passwords from digests. We examined brute force attack to get the original passwords from the hashed ones and studied some existing GPU-based brute force cracking tools. These applications implement a hybrid algorithm that generates available passwords on CPU side and hashes them in parallel on GPU side. In this paper, we propose a new homogeneous parallel brute force cracking algorithm that performs all the works on GPU side. In our experiments, we successfully cracked many kinds of passwords. For example, with 6-digit passwords, it took about 0.23 ms for initialization, 1.97 ms for combination generation, and 52.81 ms for brute-force. So we need less than 1 second to crack passwords of this kind.