Solar Designer



Passwords (or phrases) remain a distinct and ubiquitous authentication factor. They are also widely used to derive encryption keys for data or other keys. Password cracking is used in security audits, penetration testing, to recover or gain access to data, keys, or funds, and for a variety of other purposes. Focus of this talk is evolution and optimization of offline password cracking. At a high level, we break down the optimization problem into that of speed (how many candidate passwords we test per second) and focus (which candidate passwords we test against which targets and in what order). Also included is plenty of historical context starting with 1960s and until the present day, with a look into the future.

Password cracking may be simple on the surface, but it is also serious computer science and engineering and is still an evolving and highly competitive field welcoming new contributors. Like with other offensive security fields, new techniques and results inform design and parameters of new defenses.



Alexander Peslyak, better known as Solar Designer, is the founder of Openwall, a community project and professional services company focused on security of Open Source software. He achieved a number of “”firsts”” in (anti-)exploitation of memory corruption vulnerabilities, co-authored much of Openwall’s software including John the Ripper and other password security tools, runs the oss-security and (linux-)distros mailing lists – among many other past and current activities. Alexander spoke at numerous international conferences.