entropy measures

[Eric Hughes <hughes@soda.berkeley.edu>]

Dean:
>Where does uuencoded [compressed] binary lie?  I would suspect it lies
>right around where encrypted text is.  

Right.

>Presumably straight encrypted
>text is statistically random [7..8], but that when you encrypt to
>just the ascii subset is when you lose the entropy.

Exactly.

uuencoding will have a slightly lower single-character entropy than
the ASCII armor PGP uses because just about every line begins with the
letter 'M'.  This will skew the distribution slightly.  But a better
way of distinguishing uuencoding and ascii armor is to see that in
falls in the same entropy class, and then just looking at the
alphabetic subsets used.

Eric