This uses a trick I've thought about trying for several weeks, and finally got around to doing. It turned out much better than I had expected.
After it was working the way I liked, I did a search through past obfuscations at Perlmonks to make sure nobody else had done this before. The only other submission I found which uses crypt was this one, but its method is significantly different.
One of the nice things about using crypt is that running perl -MO=Deparse on it doesn't give anything away.
(I decided to create a signature based on the idea, too, which I'll use for the first time here).
@::=qw'79 11 34 69 41 27 2 4 4 2 5 4';
@::_=map{$x=pop@::;(crypt$_.' ',shift@::)=~/..(.{$x}).*/g}
split/ /, 'writing Library. Building consider TO($FOO) *binary*';
map{print;/^[Hea]/ or print ' '}(@::_,',',$/)
@ARGV=split//,"/:L";
map{print substr crypt($_,ord pop),2,3}qw"PerlyouC READPIPE provides"
