# Time to guess a 100-bit key at one billion operations per second and one billion cores?

My math is as follows. If you can do one billion operations per second on a single core, and you have one billion cores available, that translates to $$2^{60}$$ operations per second, and $$2^{100}$$/$$2^{60}$$ = $$2^{40}$$ seconds, which translates to ~35,000 years.

Increase the key length to 128 bits, and the time required becomes greater than the age of the universe.

Is the math here correct?

• @PaulUszak Please refrain from using comments for purposes other than asking for clarification or making suggestions to improve the question. Jan 23 '19 at 2:14