CipherSaber 2 in ruby

gistfile1.rb

#!/usr/bin/env ruby

class CS;def d(t,k,n);r=[];s=(0..255).to_a;j=0;k.each_byte{|b|r<<b};n.times{0.upto(255){|i|j=(j+s[i]+r[i%r.length])%256;
s[i],s[j]=s[j],s[i]}};i,j=0,0;c="";t.each_byte{|b|i=(i+1)%256;j=(j+s[i])%256;s[i],s[j]=s[j],s[i];k=s[(s[i]+s[j])%256];c<<(k^b)};c;end;end

class CipherSaber < CS
    def initialize(key,num)
      @key = key
      @num = num
    end

    def decrypt(text)
      d(text,@key.clone,@num)
    end

    alias :encrypt :decrypt
end