What do La Croix, octonions, and Second Life have in common?

Summary: Trail of Bits contributed two cryptography challenges to CSAW CTF, including "Holywater," which implemented the HK17 post-quantum key exchange built on octonions and was solved by nine teams during the qualifiers. The finals portion, "Holywater 2: La Croix," ran inside Second Life using Linden Scripting Language and unit quaternions, and only MIT and CMU found the final flag.
What's compelling: HK17 was proposed as a quantum-hard key exchange, yet it reduced to four variables in four linear equations and fell to college students over a weekend - a reminder that a scheme's difficulty claims deserve adversarial testing before anything is built on them.

Read the original at Trail of Bits Blog ↗