The president of the United States says he's not "allowed" to own an iPhone, which is why he's sticking with his BlackBerry, according to The Wall Street Journal.It's a politically sensitive subject because the iPhone is the big American brand, and the president is a self-proclaimed fan of the late Apple founder and CEO Steve Jobs. He'd love to pander to buy-America voters. (Obama is also probably not "allowed" to have an Android phone.)Of course, neither the president nor the Secret Service is willing to say exactly how security could be compromised with an iPhone. But one security risk is the unpredictable nature of both iPhone and Android apps.Sure, there's a lot of flat-out malware flying around onlin