About 128-bit encryption keys:

“Complexities are expressed as orders of magnitude. If an algorithm has a processing complexity of 2¹²⁸, then 2¹²⁸ operations are required to break the algorithm. (These operations may be complex and time-consuming).
Still, if you assume that you have enough computing speed to perform a million operations every second and you set a million parallel processors against the task, it will still take over 10⁹ years to recover the key. That’s a billion times the age of the universe.”

from this cryptography book.

Impressive? Yes. But there’s a flaw on this theory: technology is not constant over time. More processing power together with brains writting more efficient cracking algorithms is all that will take to get 128-bit keys breakable during my life time. And that’s what I call impressive.