Sorry to contribute to the simply awesome noise to signal ratio here lately (hopefully the subject tag should help those not interested in politics), but... [if you don't know what I'm talking about, see http://www.dcs.ex.ac.uk/~aba/rsa/ for a combined perl hack and ITAR violation] Due mainly to a couple of insights donated by someone who was introduced to the code via a friends `munition' T-shirt... he started the ball rolling again... it shrunk from: #!/bin/perl -s-- -export-a-crypto-system-sig -RSA-3-lines-PERL $m=unpack(H.$w,$m."\0"x$w),$_=`echo "16do$w 2+4Oi0$d*-^1[d2%Sa 2/d0<X+d*La1=z\U$n%0]SX$k"[$m*]\EszlXx++p|dc`,s/^.|\W//g,print pack('H*',$_)while read(STDIN,$m,($w=2*$d-1+length($n)&~1)/2) to: #!/bin/perl -sp0777i<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<j]dsj $/=unpack('H*',$_);$_=`echo 16dio\U$k"SK$/SM$n\EsN0p[lN*1 lK[d2%Sa2/d0$^Ixp"|dc`;s/\W//g;$_=pack('H*',/((..)*)$/) (Actually it's not quite as impressive as it might look at first glance because the old version included the comment "-export-a- crypto-system-sig -RSA-3-lines-PERL", so the new one should really be compared against: #!/bin/perl -s $m=unpack(H.$w,$m."\0"x$w),$_=`echo "16do$w 2+4Oi0$d*-^1[d2%Sa 2/d0<X+d*La1=z\U$n%0]SX$k"[$m*]\EszlXx++p|dc`,s/^.|\W//g,print pack('H*',$_)while read(STDIN,$m,($w=2*$d-1+length($n)&~1)/2) ) but it's still a whole 31 bytes shorter, and it now really is in 3 lines of perl rather than cheating and not counting the #!/bin/perl line. (Several people took me to task on that one). I won't consume list bandwidth describing exactly how the new one works, and the arcane perl and dc hackery that went into it, as I have described it all in excruciating detail on: http://www.dcs.ex.ac.uk/~aba/rsa/story.html I really wasn't expecting to see it shortened any further. There goes all those T-shirts, outdated, my sincere apologies to Richard White also, whose tattoo was featured in the April issue of Wired (at least the UK edition, the US one too?), Oh yeah, and if you can see any ways to shorten it, please tell me! (Perl5 specifics not allowed, there is already a shorter p5 specific version but it's got to be as portable as possible). Adam ps I now have a reasonable stock of T-shirts again after the prolonged hiatus of my printer, who finally delivered the 2nd batch. -- #!/bin/perl -sp0777i<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<j]dsj $/=unpack('H*',$_);$_=`echo 16dio\U$k"SK$/SM$n\EsN0p[lN*1 lK[d2%Sa2/d0$^Ixp"|dc`;s/\W//g;$_=pack('H*',/((..)*)$/)