

Hmm, here are a couple:

1) If the algorithm becomes known, it will be easy to produce
pin-compatible non-crippled chips that provide -real- encryption and
privacy, because their keys are only in their users' hands.

2) Since SkipJack is a symmetric key cypher, it needs some way to
agree on a session key. The released information says that any
protocol may be used (e.g., DH). From a theoretical point of view,
this is probably true. However, from a practical point of view, those
chips must have some kind of key exchange protocol built-in. What if
it is good old RSA? This will mean that the producer will have to pay
lots of bucks to PKP. By keeping the details secret this can be
avoided...

Regards,
Vesselin