Modern computing systems are under attack by increasingly motivated and sophisticated attackers. Recently, the Meltdown and Spectre attacks have demonstrated that security is not only a software problem, but that the hardware components can expose software-exploitable vulnerabilities. These attacks exploit the core paradigm used to build modern high performance CPUs: speculative out of order execution. It is not clear how to build CPUs that are both secure and performant. In this talk, I will first introduce these attacks using examples of SpectreRSB, a speculation attack that exploits the Return Stack Buffer, which is a structure in modern processors used to predict the return address of a function. I will then discuss two ideas to build next generation CPUs to enable secure speculation without sacrificing performance. In particular, SafeSpec hides the effects of speculation until an instruction is committed. In contrast, SpecCFI leverages principles of control flow integrity to restrict speculation to occur only to legal points within the program.