encoded clone create encoded clone

encode_clone.rb

# http://pam-ya.com/blog/archives/2006/04/post-238.html
$code = <<-EOS
require 'openssl'
require 'base64'
class Clone
  def generate
    file_name = 'sample_' + Time.now.strftime('%F-%H%M%S%L') + '.rb'
    File.open(file_name, 'w') do |f|
      header = '$code = <<-EOS'
      footer = 'EOS'
      f.puts 'require "openssl"'
      f.puts 'require "base64"'
      f.puts header
      f.puts encrypt(header + "\n" + $code + footer + "\neval $code")
      f.puts footer
      f.puts "def decrypt(str)"
      f.puts "  decode = Base64.strict_decode64(str.chomp)"
      f.puts "  cipher = OpenSSL::Cipher.new('" + mode + "')"
      f.puts "  cipher.decrypt"
      f.puts "  key_iv = OpenSSL::PKCS5.pbkdf2_hmac_sha1('" + pass + "', '" + salt + "', " + iter.to_s + ", cipher.key_len + cipher.iv_len)"
      f.puts "  key = key_iv[0, cipher.key_len]"
      f.puts "  iv = key_iv[cipher.key_len, cipher.iv_len]"
      f.puts "  cipher.key = key"
      f.puts "  cipher.iv = iv"
      f.puts "  decrypted_data = ''"
      f.puts "  decrypted_data << cipher.update(decode)"
      f.puts "  decrypted_data << cipher.final"
      f.puts "  decrypted_data"
      f.puts "end"
      f.puts "eval decrypt($code)"
    end
  end

  def salt
    @_salt ||= ('A'..'z').to_a.sample(8).join
  end

  def pass
    @_pass ||= ('A'..'z').to_a.sample(10).join
  end

  def iter
    2000
  end

  def mode
    'AES-256-CBC'
  end

  def encrypt(str)
    cipher = OpenSSL::Cipher.new(mode)
    cipher.encrypt
    key_iv = OpenSSL::PKCS5.pbkdf2_hmac_sha1(pass, salt, iter, cipher.key_len + cipher.iv_len)
    key = key_iv[0, cipher.key_len]
    iv = key_iv[cipher.key_len, cipher.iv_len]
    cipher.key = key
    cipher.iv = iv
    cipherrypted_data = ''
    cipherrypted_data << cipher.update(str)
    cipherrypted_data << cipher.final
    Base64.strict_encode64(cipherrypted_data)
  end
end
Clone.new.generate
EOS

eval $code