Which is grammatically consistent with the assertion that fundamentally nothing has changed: certificates with a 63-bit serial number are unlikely to be compromised and certificates with a valid 64-bit serial number are also unlikely to be compromised.
Yes the previous value was not infinity. It was impractical to solve in a human lifetime, but if they keep trimming off a few bits it very quickly becomes practical. If actually "infinity" then dividing it by any finite number would still result in infinity, which is not the case here.
Right, which is why the specific claim here is that 63 is not a problem, not that smaller numbers in general are not a problem.
A better way to put this: instead of saying "it reduces the search space by 9 quintillion," say "it reduces 50% of the search space." Sure, that's a lot, but not nearly as much as trimming 8 bits and saying "it reduces 99.6% of the search space."
There should be a very large gap between "theoretically impossible" and "practical". If cutting the search space in half gets you from one to the other, there's probably been an error in definition.
A $32 million (1985 dollars) Cray 2 super computer could do 1.9GFlops.
You can now get over 50x that performance for less than a grand in a device that fits in your pocket. I bet those engineers didn't expect that in half a lifetime.
That's rather beside the point. If 63 bits is insecure, then 64 bits is also insecure. If I can brute force 63 bits in a week, I can brute force 64 bits in 2 weeks. If we are worried that 63 bits is a security issue, then the solution isn't increasing to 64 bits, it's increasing to 96 bits, or 128 bits.
Moore's law was described in 1965 and the experimental evidence lined up for well past the next two decades. If you handwave exactly what it means to "everything is 2x better every 1.5 years," we'd expect a factor of 2^(30 / 1.5) = 1 million by 2015, so having a factor of 100,000x in cost and having it fit in your pocket wasn't actually unexpected.
Certainly any cryptosystems designed in 1985 that wanted to encrypt data until today should have taken the most aggressive form of Moore's Law into account.
