There is a saying in security - "attacks only get better". At DEF CON 23, a tool called "brainflayer" was released, able to crack Bitcoin keys generated from passwords. Work has continued on it with the addition of a slew of optimizations that have more than quadrupled the speed, and features to crack other cryptocurrencies and weak key generation techniques.
Many password cracking tools, including brainflayer, have optimizations in how they compute and look up hashes, but when cracking Bitcoin keys the biggest bottleneck is computing public keys from private keys. This talk will cover the various techniques used to make that faster, some special case optimizations, touch on how more general tricks are applied, and go over new features since release.
Ryan Castellucci has been interested in cryptography and computer security since childhood. He has been doing work on Bitcoin key cracking for several years, first presenting on it at DEF CON 23. By day, Ryan does browser security research to detect bots, scrapers and other forms of automated http clients for White Ops. He's on twitter as @ryancdotorg and blogs sporadically at https://rya.nc/