Document Type

Conference Proceeding

Publication Date



John the Ripper, passwords, algorithm


John the Ripper (JtR) is an open source software package commonly used by system administrators to enforce password policy. JtR is designed to attack (i.e., crack) passwords encrypted in a wide variety of commonly used formats. While parallel implementations of JtR exist, there are several limitations to them. This research reports on two distinct algorithms that enhance this password cracking tool using the Message Passing Interface. The first algorithm is a novel approach that uses numerous processors to crack one password by using an innovative approach to workload distribution. In this algorithm the candidate password is distributed to all participating processors and the word list is divided based on probability so that each processor has the same likelihood of cracking the password while eliminating overlapping operations. The second algorithm developed in this research involves dividing the passwords within a password file equally amongst available processors while ensuring load-balanced and fault tolerant behavior. This paper describes John the Ripper, the design of these two algorithms and preliminary results. Given the same amount of time, the original JtR can crack 29 passwords, whereas our algorithms 1 and 2 can crack an additional 35 and 45 passwords respectively.


Faculty of Applied Science & Technology


School of Applied Computing


Journal of Physics: Conference Series


Publisher's version

Peer Reviewed/Refereed Publication


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Creative Commons License

Creative Commons Attribution 3.0 License
This work is licensed under a Creative Commons Attribution 3.0 License.

Original Publication Citation

Sykes, E. R., Lin, M., Skoczen, W. (2010). MPI enhancements in John the Ripper. Journal of Physics: Conference Series, 256(1) doi:10.1088/17426596/256/1/012024


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