My second japh and I'm a little more satisfied with this one. I did want to put it into a shape but I couldn't find one :/.

$a=sub{$_=shift;s/(\d)(\d)/$2$1/;return ++$|.$_;};
$b=sub{$/=shift;substr($/,shift,1,'1');$/;};
$c=sub{unpack("N",pack("B32",substr("$["x 32 . shift,-32)))};
undef $d;
print pack("a1b8c1i1",
chr(&{$a}(&{$c}($[.&{$a}($[.'1')).$[)),
substr(&{$a}($[.$[).join('',reverse(split('',&{$a}($[.$[)))).&{$a}($[.
+$[),$[,&{$c}(&{$a}($[.$[).$[)),
&{$b}(&{$b}(&{$b}(&{$a}($[.$[).$[x5,++$d),++$d),++$d),
&{$a}(&{$c}($[.&{$a}($[.$[)).$[)
);
[download]

I think the subs kind of give it away though - does anyone have any hints? Cheers :)
Simon Proctor