For various reasons, including the patent status of commonly used compression
schemes and related legal matters, we elected not to specify any standard
compression systems in the RFC. BASE64 is similar to UUENCODE but not the
same; it is fully documented so you can compare the encoding yourself if you
want to. There are a number of reasons for avoiding UUENCODE -- its use of
spaces makes it less than reliable in mail systems (trailing blank suppression
is a fairly common phenomenon), the chosen scheme is compatible with
the scheme used for privacy enhanced mail, and finally the BASE64 scheme
is somewhat cleaner in several ways than what UUENCODE uses.
Another possible encoding candidate is BASE85. This is specified in the
PostScript level 2 documentation. It is 5% better than BASE64, but does
require multiplication and division to compute. It does not have problems
with the characters it uses. Anyone interested in this additional encoding?