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Did you know you could evaluate a polynomial over GF(128) in perl with pack and unpack and tr? Here's how.

sub h { $_ = $_[0] = pack b208, 0 . unpack b362, $_[0]; tr/\0-\c?/\0/; tr/\0/\377/c; $_ } for (split //, "k6sNP2B}({ambrusLB%Ox)Z]n0*zf\0I3") { $y = $r; $v = join $r = '', a .. z; $r ^= h($r) & "\217" x 26 ^ h($v) & $y for 0 .. 6; $r ^= $_ x 26; } print $r;

This code is based on the same idea as Dollar Plus, but written in a different style, so some of the credit goes to martin.

Update: if you prefer one of these unreadable blocks of code, you can of course write this that way too (Update: reformatted blob from four lines to three.)

sub h($){($_=$_[0]=pack b208,0 .unpack b362,$_[0])=~tr/\0-\c?/\0/;tr /\0/\377/c;$_}do{$y=$r;$v=join$r='',a..z;$r^=h$r&"\217"x26^h$v&$y for 0..6;$r^=$_ x26}for"k6sNP2B}({ambrusLB%Ox)Z]n0*zf\0I3"=~/./g;print$r

Update: removed lots of spaces from end of lines of formatted code.


In reply to Japh algebra, GF(128) edition by ambrus

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