

Thousands?  Tens of thousands?  Do some arithmetic, please...  Skipjack
has 2^80 possible keys.  Let's assume a brute-force engine like that
hypothesized for DES:  1 microsecond per trial, 1 million chips.  That's
10^12 trials per second, or about 38,000 years for 2^80 trials.  Well,
maybe they can get chips running at one trial per nanosecond, and build
a machine with 10 million chips.  Sure -- only 3.8 years for each solution.

IDEA uses 128-bit keys.  Shall I bother doing the calculations for you?
Hint:  multiply 3.8 years by 2^(128-80).  And you can't do IDEA at that
speed; key setup takes much too long.  I wouldn't be surprised if that
were the case for Skipjack, too, though there's no way of knowing just
yet.  DES used only xor because that's what was feasible with mid-70's
technology.  Modern chips can do a lot more.