The minimum key length for the AES algorithm is 128 bit. Assume that a special-purpose hardware key-search machine can test one key in 10 ns on one processor.
The processors can be parallelized. Assume further that one such processor costs $10, including overhead. (Note that both the processor speed and the prize are rather optimistic assumptions.) We assume also that Moore's Law holds, according to which processor performance doubles every 18 months.
How long do we have to wait until an AES key search machine can be built which breaks the algorithm on average in one week and which doesn't cost more than $1 million?