If all I do is turn a computer on, will it take the same number of nanoseconds to reach the boot screen? If you think the answer is yes, PoC ∥ GTFO. If you think the answer is no, that there will be some amount of nanosecond drift, then where does this drift come from? The answer is that the biggest lie about your computer is that it’s just one computer. CPU cores talk to memory busses talk to expansion busses talk to storage and networking and the interrupt of the month club. There are generally some number of clocks, they have different speeds and different tolerances, and you do not get them synchronized for free. (System-on-Chip devices are a glaring exception, but it’s still rather common for them to be speaking to peripherals.) Merely turning the machine on does not synchronize everything, so there is drift. Where there is drift, there is entropy. Where there is entropy, there is security.
Zitat des Tages
Written by georg on November 26, 2017