# File lib/openid/filestore.rb, line 273
    def filename_from_url(url)
      filename = []
      url.sub('://','-').split("").each do |c|
        if @@FILENAME_ALLOWED.index(c)
          filename << c
        else
          filename << sprintf("_%02X", c[0])
        end    
      end
      filename.join("")
    end