Not let the swf to download


I want to know is there any script or method for not to let swf file to download into the viewer’s temporary internet folder .I know there is way , I saw lots of flash gaming sites where the actual flash file does not get downloaded and it can only be watched online. I want to protect my swf from tempering. I kown there are encryptors for this but may be in future there will be new versions of decompilers to overcome this . I think the best way to protect my swf file is that nobody gets it without my knowlege.