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.