1 gigahertz is about 1 billion cycles per second, so, assuming you could evaluate 1 possibility per machine cycle (in reality, it takes many more than 1 cycle to evaluate 1 possibility) you can take 9 of the zeroes off that number, to get the number of seconds your i5 would require.
As
@Tom.G so clearly and capably put it:
Subtracting 9 from the 10s exponent of 95
17 ≈ 4.18×10
33 leaves ≈ 4.18×10
24. Dividing that by 60 seconds per minute, and by 1440 minutes per day, and by 365 days per year, we get 130,010,147,133,435,000 years. That's (US) 130 quadrillion, 10 trillion, 147 billion, 133 million, 435 thousand.
The fastest publicly displayed machines (measured in floating-point instructions per second, rather than in cpu cycles per second), about 5 years ago, were
petascale computers, and they looked something like this:
View attachment 227878View attachment 227879
That installation, at Argonne (my neck of the woods -- no I don't work there -- just a sometimes visitor), had 164,000 processor cores, each of them much faster than a 3 gigahertz i5. This one, from last year, at Oak Ridge:
View attachment 227880
runs at over over 200 petaflops (thousand teraflops = petaflops = quadrillions of floating point instructions per second.
Skipping teraflops (thousand gigaflops), petaflops allows us to take the 10
24 down to 10
18 and exaflops bring us down to ≈ 4.18E15 seconds. Dividing that again, we get ≈ (((4.18E15)/60)/1440)/365 years -- that's still over a century (> 13 decades), even if we really could evaluate 1 possibility per floating point instruction, which we can't, at least not directly.
The fastest that NSA can muster is at least in the multi-exaflop range -- the first https://en.wikipedia.org/wiki/Exascale_computing[/url installations to be launched publicly should/will be seen this year.
Somehow NSA is able to break hard encryptions much faster than all the foregoing exposition suggests -- anecdotally, I know of a situation in which they cracked a stash of extremely-evil-bad-guy multiply-encrypted DVDs in 1 day -- they're probably using some unpublished set of algorithms -- not only do they have the largest and most advanced computer systems; they also routinely hire all the best math and comp sci guys (and gals) they can find.
Use at least one non-letter character, and at least one uppercase and at least one lowercase letter, and at least 7 characters total, e.g. #Element12, (please don't use that one, as I just published it as an example here) which is easy enough to remember by some association, and not too easy to guess.