PERL RC4

#!/usr/local/bin/perl -- -export-a-crypto-system-sig -RC4-in-3-lines-of-PERL
@k=unpack('C*',pack('H*',shift));sub S{@s[$x,$y]=@s[$y,$x];}for(@t=@s=0..255)
{$y=($k[$i++]+$s[$_]+$y)%256;$x=$_;&S;$i%=@k;}$/=$x=$y=0;for(unpack('C*',<>))
{$x++;$y=($s[$x%=256]+$y)%256;&S;print pack(C,$_^=$s[($s[$x]+$s[$y])%256]);}