 OK, I should have read the thread before posting my own $0.02.  I would
just add to Phil's very infomative discussion the following caveat: the
fifth amendment applies ONLY in crinial cases.  ("...nor shall any person .
. . be compelled in any criminal case to be a witness against himself...").
Thus if the father sued for custody of the children, the case would be
civil and the defendant mother would not have fifth amendment protection.
Oddly enough, her refusal to give information in a civil case can lead to
criminal contempt charges (thus landing her in jail.)  The interesting part
of all this is that in a murder trial, the woman CAN plead the fifth as 
to the location of the child--this is routine.  A "computer crime" 
prosecution thus would seem to be fertile ground for this kind of defense, 
where a suit by a party injured by "hackers" would not.  If I am accused, 
for example, of sending encrypted kiddie porn over the nets the fifth should 
protect my key.  If I am accused of sending copyrighted material, however,
it proabably will not (copyright infringement not being a "crime" in the
technical sense.)  The REALLY tricky question is, say I do both (naughty
boy that I am) can the government use the information gained in the civil
trial (ie. my key) to gain access to my files for use in the criminal
prosecution.  The answer should certainly be no, but lord only knows how
this would work out.

Steve.
 
