[gitgudnubs]

There are more hardware exploits. New classes of exploits using physics and side-channels are circumventing the formal models used to build CPUs.

CPU designers have made complex architectural decisions to speed up execution. In the case of spectre, it's to speed up single-threaded execution. In the case of this, it's to optimize security features. An analogous case is AES256, which was chosen because it's fast. But it's fast because the s-boxes use the private key as an index into an array, so there's caching. But this introduces a side-channel, because based on time to execute you can infer the private key.