This talk is going to tell the tale of a critical security vulnerability that was found a year after launch on the RK3288 ("veyron") family of Chromebooks and allowed bypassing the entire secure boot stack. It will explain the technical details of this vulnerability, why it was overlooked in the first place, the tricky process to mitigate it, and finally give a real answer to this guy's stack overflow question: https://superuser.com/questions/1399681/what-is-the-gpt-header-signature-for