A slightly less simple obfuscation for a slightly less simple substitution cipher. The next stop in my tour of old forgotten encryption ciphers is this skytale implementation. This either takes a file as a parameter to encrypt in skytale, or provided no input encrypt's it's __DATA__.

#!/usr/bin/perl

open DATA,$ARGV[0]if$ARGV[0];$;=$0=~y~a-z~~;map{m'(\d+)(?{$*=chr$,+65;
+push@{$*},
$^N;$.{$*}++;$,=$,<$;?++$,:0})'}grep!/^10$/,map ord,split//,join'',<DA
+TA>; print
join '' , map chr , @ $_ for 'A' .. ( sort keys ( % . ) ) [ -1 ] ;  pr
+int "\n" ;

__DATA__
In cryptography, a scytale (also known as skytale) is a tool used to p
+erform a
transposition cipher, consisting of a cylinder w/ a strip of paper wou
+nd around
it on which is written a message across the windings, with the ciphert
+ext
consisting of the unwound paper.  This is one way to implement such a 
+cipher.
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$,=42;for(34,0,-3,9,-11,11,-17,7,-5){$*.=pack'c'=>$,+=$_}for(reverse s
+plit//=>$*
){$%++?$ %%2?push@C,$_,$":push@c,$_,$":(push@C,$_,$")&&push@c,$"}$C[$#
+C]=$/;($#C
>$#c)?($ c=\@C)&&($ C=\@c):($ c=\@c)&&($C=\@C);$%=$|;for(@$c){print$_^
+$$C[$%++]}
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