Pwnium 4 will be hosted in March at the CanSecWest security conference in Vancouver. Researchers can choose an ARM-based Chromebook, the HP Chromebook 11 (WiFi), or the Acer C720 Chromebook (2GB WiFi) that is based on the Intel Haswell microarchitecture. The attack must be demonstrated against one of these devices running the then-current stable version of Chrome OS. The deliverable is the full exploit, with explanations for all individual bugs used (which must be unknown)”]
Source: https://blog.chromium.org/2014/01/show-off-your-security-skills.html