Student(s): Hao Xu; Title: Improving Rainbow Table Cracking Accuracy; Mentor(s): Xianping Wang, CITG. Abstract: Password cracking is the process of recovering plaintext passwords from data that has been stored in or transmitted by computing systems in cryptanalysis, computer security and digital forensics. There are many situations that require password cracking: helping users recover forgotten passwords, gaining unauthorized access to systems, checking password strength, etc. The most popular and applicable password cracking method is brute-force attack with various improvements such as dictionary attack, rainbow table attack. Usually they are accelerated with GPU, FPGA and ASIC. As passwords are usually stored in their hash codes instead of plaintext. to accelerate the password cracking process, caching the output of cryptographic hash codes of passwords, named as rainbow table, are used widely today. However, rainbow tables are usually created from exhaustive password dictionaries, in which many unusual combinations of letters, symbols and digits are contained, which decreased cracking efficiency and accuracy The efficiency and accuracy of rainbow table cracking can be improved from many aspects such as password patterns, computing engines, etc. In this research, we will employ many openly available leaked passwords, to find their distribution by maximum likelihood estimation, design a password generator based on the found distribution, generate rainbow tables on the passwords generated by the designed password generator. The accuracy of our rainbow table cracker will be compared with several popular password crackers --- John the Ripper password cracker, Cain and Abel, Hashcat , and Ophcrack " .