rc4_decoder.rb

require 'rc4'

if ARGV.size != 1
  puts "Usage: #{$0} <key>|<content>\n\n"
  exit 1
end

(key, cypher_text) = ARGV[0].split('|')

key = key.split('').sort.join

rc4 = RC4.new(key)

s = cypher_text.scan(/../).collect{|x| [x.hex].pack('C')}.join

puts rc4.decrypt(s)