Well, we cheated a bit


This isn't really true, since computers get faster over time

A better strategy for breaking 128-bit crypto is just to wait until computers get 2^88 times faster, then break it on one computer in 3 days.
How long do we wait?  Moore's law says 132 years.
If we believe Moore's law will keep on working, we'll be able to break 128-bit crypto in 132 years (and 3 days) :-)

An even better strategy: don't break the crypto at all!
There are always weaker parts of the system to attack
More on this later