The 2017 Pwnie Award For Best Cryptographic Attack
The first collision for full SHA-1
The SHAttered attack team generated the first known collision for full SHA-1. The team produced two PDF documents that were different that produced the same SHA-1 hash. The techniques used to do this led to an a 100k speed increase over the brute force attack that relies on the birthday paradox, making this attack practical by a reasonably (Valasek-rich?) well funded adversary. A practical collision like this, moves folks still relying on a deprecated protocol to action.